release 3.5.2

also check whether EventQueue.push() succeeded; if not, disable submenu safe triangle

.github/workflows/ci.yml

@@ -32,10 +32,12 @@ jobs:
           - 8
           - 11  # LTS
           - 17  # LTS
+          - 21  # LTS
+          - 23  # latest
         toolchain: [""]
-        include:
-          - java: 17
-            toolchain: 21  # latest
+#        include:
+#          - java: 21
+#            toolchain: 22  # latest
 
     steps:
       - uses: actions/checkout@v4
@@ -47,7 +49,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           java-version: ${{ matrix.java }}
-          distribution: temurin  # Java 8, 11 and 17 are pre-installed on ubuntu-latest
+          distribution: temurin  # Java 8, 11, 17 and 21 are pre-installed on ubuntu-latest
           cache: gradle
 
       - name: Check with Error Prone

CHANGELOG.md

@@ -1,6 +1,141 @@
 FlatLaf Change Log
 ==================
 
+## 3.5.2
+
+#### Fixed bugs
+
+- Windows: Fixed repaint issues (ghosting) on some systems (probably depending
+  on graphics card/driver). This is done by setting Java system property
+  `sun.java2d.d3d.onscreen` to `false` (but only if `sun.java2d.d3d.onscreen`,
+  `sun.java2d.d3d` and `sun.java2d.noddraw` are not yet set), which disables
+  usage of Windows Direct3D (DirectX) onscreen surfaces. Component rendering
+  still uses Direct3D. (issue #887)
+- FlatLaf window decorations:
+  - Iconify/maximize/close buttons did not fill whole title bar height, if some
+    custom component in menu bar increases title bar height. (issue #897)
+  - Windows: Fixed possible application freeze when using custom component that
+    overrides `Component.contains(int x, int y)` and invokes
+    `SwingUtilities.convertPoint()` (or similar) from the overridden method.
+    (issue #878)
+- TextComponents: Fixed too fast scrolling in multi-line text components when
+  using touchpads (e.g. on macOS). (issue #892)
+- ToolBar: Fixed endless loop if button in Toolbar has focus and is made
+  invisible. (issue #884)
+
+#### Other Changes
+
+- FlatLaf window decorations: Added client property `JRootPane.titleBarHeight`
+  to allow specifying a (larger) preferred height for the title bar. (issue
+  #897)
+- Added system property `flatlaf.useRoundedPopupBorder` to allow disabling
+  native rounded popup borders on Windows 11 and macOS. On macOS 14.4+, where
+  rounded popup borders are disabled since FlatLaf 3.5 because of occasional
+  problems, you can use this to enable rounded popup borders (at your risk).
+
+
+## 3.5.1
+
+#### Fixed bugs
+
+- HTML: Fixed occasional cutoff wrapped text when using multi-line text in HTML
+  tags `<h1>`...`<h6>`, `<code>`, `<kbd>`, `<big>`, `<small>` or `<samp>`.
+  (issue #873; regression in 3.5)
+- Popup: Fixed `UnsupportedOperationException: PERPIXEL_TRANSLUCENT translucency
+  is not supported` exception on Haiku OS when showing popup (partly) outside of
+  window. (issue #869)
+- HiDPI: Fixed occasional wrong repaint areas when using
+  `HiDPIUtils.installHiDPIRepaintManager()`. (see PR #864)
+- Added system property `flatlaf.useSubMenuSafeTriangle` to allow disabling
+  submenu safe triangle (PR #490) for
+  [SWTSwing](https://github.com/Chrriis/SWTSwing). (issue #870)
+
+
+## 3.5
+
+#### New features and improvements
+
+- Table: Support rounded selection. (PR #856)
+- Button and ToggleButton: Added border colors for pressed and selected states.
+  (issue #848)
+- Label: Support painting background with rounded corners. (issue #842)
+- Popup: Fixed flicker of popups (e.g. tooltips) while they are moving (e.g.
+  following mouse pointer). (issues #832 and #672)
+- FileChooser: Wrap shortcuts in scroll pane. (issue #828)
+- Theme Editor: On macOS, use larger window title bar. (PR #779)
+
+#### Fixed bugs
+
+- macOS: Disabled rounded popup border (see PR #772) on macOS 14.4+ because it
+  may freeze the application and crash the macOS WindowServer process (reports
+  vary from Finder restarts to OS restarts). This is a temporary change until a
+  solution is found. See NetBeans issues
+  [apache/netbeans#7560](https://github.com/apache/netbeans/issues/7560#issuecomment-2226439215)
+  and
+  [apache/netbeans#6647](https://github.com/apache/netbeans/issues/6647#issuecomment-2070124442).
+- FlatLaf window decorations: Window top border on Windows 10 in "full window
+  content" mode was not fully repainted when activating or deactivating window.
+  (issue #809)
+- Button and ToggleButton: UI properties `[Toggle]Button.selectedForeground` and
+  `[Toggle]Button.pressedForeground` did not work for HTML text. (issue #848)
+- HTML: Fixed font sizes for HTML tags `<h1>`...`<h6>`, `<code>`, `<kbd>`,
+  `<big>`, `<small>` and `<samp>` in HTML text for components Button, CheckBox,
+  RadioButton, MenuItem (and subclasses), JideLabel, JideButton, JXBusyLabel and
+  JXHyperlink. Also fixed for Label and ToolTip if using Java 11+.
+- ScrollPane: Fixed/improved border painting at 125% - 175% scaling to avoid
+  different border thicknesses. (issue #743)
+- Table: Fixed painting of alternating rows below table if auto-resize mode is
+  `JTable.AUTO_RESIZE_OFF` and table width is smaller than scroll pane (was not
+  updated when table width changed and was painted on wrong side in
+  right-to-left component orientation).
+- Theme Editor: Fixed occasional empty window on startup on macOS.
+- FlatLaf window decorations: Fixed black line sometimes painted on top of
+  (native) window border on Windows 11. (issue #852)
+- HiDPI: Fixed incomplete component paintings at 125% or 175% scaling on Windows
+  where sometimes a 1px wide area at the right or bottom component edge is not
+  repainted. E.g. ScrollPane focus indicator border. (issues #860 and #582)
+
+#### Incompatibilities
+
+- ProgressBar: Log warning (including stack trace) when uninstalling
+  indeterminate progress bar UI or using `JProgressBar.setIndeterminate(false)`
+  not on AWT thread, because this may throw NPE in `FlatProgressBarUI.paint()`.
+  (issues #841 and #830)
+- Panel: Rounded background of panel with rounded corners is now painted even if
+  panel is not opaque. (issue #840)
+
+
+## 3.4.1
+
+#### Fixed bugs
+
+- SplitPane: Update divider when client property `JSplitPane.expandableSide`
+  changed.
+- TabbedPane: Fixed swapped back and forward scroll buttons when using
+  `TabbedPane.scrollButtonsPlacement = trailing` (regression in FlatLaf 3.3).
+- Fixed missing window top border on Windows 10 in "full window content" mode.
+  (issue #809)
+- Extras:
+  - `FlatSVGIcon` color filters now support linear gradients. (PR #817)
+  - `FlatSVGIcon`: Use log level `CONFIG` instead of `SEVERE` and allow
+    disabling logging. (issue #823)
+  - Added support for `JSplitPane.expandableSide` client property to
+    `FlatSplitPane`.
+- Native libraries: Added API version check to test whether native library
+  matches the JAR (bad builds could e.g. ship a newer JAR with an older
+  incompatible native library) and to test whether native methods can be invoked
+  (some security software allows loading native library but blocks method
+  invocation).
+- macOS: Fixed crash when running in WebSwing. (issue #826; regression in 3.4)
+
+#### Incompatibilities
+
+- File names of custom properties files for nested Laf classes now must include
+  name of enclosing class name. E.g. nested Laf class `IntelliJTheme.ThemeLaf`
+  used `ThemeLaf.properties` in previous versions, but now needs to be named
+  `IntelliJTheme$ThemeLaf.properties`.
+
+
 ## 3.4
 
 #### New features and improvements
@@ -23,8 +158,8 @@ FlatLaf Change Log
   - Improved log messages for loading fails.
 - Fonts: Updated **Inter** to
   [v4.0](https://github.com/rsms/inter/releases/tag/v4.0).
-- Table: Select all text in cell editor when starting editing using `F2` key.
-  (issue 652)
+- Table: Select all text in cell editor when starting editing using `F2` key on
+  Windows or Linux. (issue #652)
 
 #### Fixed bugs
 
@@ -52,7 +187,7 @@ FlatLaf Change Log
 #### Fixed bugs
 
 - Button and ToggleButton: Selected buttons did not use explicitly set
-  foreground color. (issue 756)
+  foreground color. (issue #756)
 - FileChooser: Catch NPE in Java 21 when getting icon for `.exe` files that use
   default Windows exe icon. (see
   [JDK-8320692](https://bugs.openjdk.org/browse/JDK-8320692))
@@ -805,7 +940,7 @@ FlatLaf Change Log
 - Native window decorations (Windows 10 only):
   - Fixed occasional application crash in `flatlaf-windows.dll`. (issue #357)
   - When window is initially shown, fill background with window background color
-    (instead of white), which avoids flickering in dark themes. (issue 339)
+    (instead of white), which avoids flickering in dark themes. (issue #339)
   - When resizing a window at the right/bottom edge, then first fill the new
     space with the window background color (instead of black) before the layout
     is updated.

README.md

@@ -33,14 +33,20 @@ FlatLaf can use 3rd party themes created for IntelliJ Platform (see
 Sponsors
 --------
 
+### Current Sponsors
+
+[![None Sponsors](images/none-sponsors.png)](https://www.formdev.com/flatlaf/sponsor/)
+
+[Become a Sponsor](https://www.formdev.com/flatlaf/sponsor/)
+
+### Previous Sponsors
+
 <a href="https://www.ej-technologies.com/"><img src="https://www.formdev.com/flatlaf/sponsor/ej-technologies.png" width="200" alt="ej-technologies" title="ej-technologies - Java APM, Java Profiler, Java Installer Builder"></a>
 &nbsp; &nbsp; &nbsp; &nbsp;
 <a href="https://www.dbvis.com/"><img src="https://www.formdev.com/flatlaf/sponsor/dbvisualizer.svg" width="200" alt="DbVisualizer" title="DbVisualizer - SQL Client and Editor"></a>
 &nbsp; &nbsp; &nbsp; &nbsp;
 <a href="https://www.dscsag.com/"><img src="https://www.formdev.com/flatlaf/sponsor/DSC.png" height="48" alt="DSC Software AG" title="DSC Software AG - Your Companion for Integrative PLM"></a>
 
-[Become a Sponsor](https://www.formdev.com/flatlaf/sponsor/)
-
 Demo
 ----
 
@@ -311,6 +317,9 @@ Applications using FlatLaf
 
 - ![New](images/new.svg) ![Sponsor](images/sponsor.svg)
   [BGBlitz](https://www.bgblitz.com/) (**commercial**) - professional Backgammon
+- ![New](images/new.svg) [MCreator](https://github.com/MCreator/MCreator) - 
+  software used to make Minecraft Java Edition mods, Minecraft Bedrock Edition Add-Ons, 
+  and data packs without programming knowledge
 - ![New](images/new.svg) [MapTool](https://github.com/RPTools/maptool) - virtual
   Tabletop for playing role-playing games
 - [MegaMek](https://github.com/MegaMek/megamek),

buildSrc/src/main/kotlin/flatlaf-cpp-library.gradle.kts

@@ -27,7 +27,7 @@ library {
 		}
 		with( linkTask.get() ) {
 			if( name.contains( "Release" ) )
-				debuggable.set( false )
+				debuggable = false
 		}
 	}
 }

buildSrc/src/main/kotlin/flatlaf-publish.gradle.kts

@@ -44,34 +44,34 @@ publishing {
 
 			pom {
 				afterEvaluate {
-					this@pom.name.set( extension.name )
-					this@pom.description.set( extension.description )
+					this@pom.name = extension.name
+					this@pom.description = extension.description
 				}
-				url.set( "https://github.com/JFormDesigner/FlatLaf" )
+				url = "https://github.com/JFormDesigner/FlatLaf"
 
 				licenses {
 					license {
-						name.set( "The Apache License, Version 2.0" )
-						url.set( "https://www.apache.org/licenses/LICENSE-2.0.txt" )
+						name = "The Apache License, Version 2.0"
+						url = "https://www.apache.org/licenses/LICENSE-2.0.txt"
 					}
 				}
 
 				developers {
 					developer {
-						name.set( "Karl Tauber" )
-						organization.set( "FormDev Software GmbH" )
-						organizationUrl.set( "https://www.formdev.com/" )
+						name = "Karl Tauber"
+						organization = "FormDev Software GmbH"
+						organizationUrl = "https://www.formdev.com/"
 					}
 				}
 
 				scm {
-					connection.set( "scm:git:git://github.com/JFormDesigner/FlatLaf.git" )
-					url.set( "https://github.com/JFormDesigner/FlatLaf" )
+					connection = "scm:git:git://github.com/JFormDesigner/FlatLaf.git"
+					url = "https://github.com/JFormDesigner/FlatLaf"
 				}
 
 				issueManagement {
-					system.set( "GitHub" )
-					url.set( "https://github.com/JFormDesigner/FlatLaf/issues" )
+					system = "GitHub"
+					url = "https://github.com/JFormDesigner/FlatLaf/issues"
 				}
 			}
 

buildSrc/src/main/kotlin/flatlaf-toolchain.gradle.kts

@@ -21,6 +21,6 @@ plugins {
 val toolchainJavaVersion = System.getProperty( "toolchain" )
 if( !toolchainJavaVersion.isNullOrEmpty() ) {
 	java.toolchain {
-		languageVersion.set( JavaLanguageVersion.of( toolchainJavaVersion ) )
+		languageVersion = JavaLanguageVersion.of( toolchainJavaVersion )
 	}
 }

flatlaf-core/build.gradle.kts

@@ -27,8 +27,8 @@ plugins {
 val sigtest = configurations.create( "sigtest" )
 
 dependencies {
-	testImplementation( libs.bundles.junit )
-	testRuntimeOnly( libs.junit.engine )
+	testImplementation( libs.junit )
+	testRuntimeOnly( libs.junit.launcher )
 
 	// https://github.com/jtulach/netbeans-apitest
 	sigtest( libs.sigtest )
@@ -42,11 +42,11 @@ java {
 tasks {
 	compileJava {
 		// generate JNI headers
-		options.headerOutputDirectory.set( layout.buildDirectory.dir( "generated/jni-headers" ) )
+		options.headerOutputDirectory = layout.buildDirectory.dir( "generated/jni-headers" )
 	}
 
 	jar {
-		archiveBaseName.set( "flatlaf" )
+		archiveBaseName = "flatlaf"
 
 		doLast {
 			ReorderJarEntries.reorderJarEntries( outputs.files.singleFile );
@@ -54,20 +54,20 @@ tasks {
 	}
 
 	named<Jar>( "sourcesJar" ) {
-		archiveBaseName.set( "flatlaf" )
+		archiveBaseName = "flatlaf"
 	}
 
 	named<Jar>( "javadocJar" ) {
-		archiveBaseName.set( "flatlaf" )
+		archiveBaseName = "flatlaf"
 	}
 
 	register<Zip>( "jarNoNatives" ) {
 		group = "build"
 		dependsOn( "jar" )
 
-		archiveBaseName.set( "flatlaf" )
-		archiveClassifier.set( "no-natives" )
-		archiveExtension.set( "jar" )
+		archiveBaseName = "flatlaf"
+		archiveClassifier = "no-natives"
+		archiveExtension = "jar"
 		destinationDirectory = layout.buildDirectory.dir( "libs" )
 
 		from( zipTree( jar.get().archiveFile.get().asFile ) )

flatlaf-core/flatlaf-core-sigtest.txt

@@ -1,5 +1,5 @@
 #Signature file v4.1
-#Version 3.4
+#Version 3.5.2
 
 CLSS public abstract interface com.formdev.flatlaf.FlatClientProperties
 fld public final static java.lang.String BUTTON_TYPE = "JButton.buttonType"
@@ -100,6 +100,7 @@ fld public final static java.lang.String TEXT_FIELD_TRAILING_COMPONENT = "JTextF
 fld public final static java.lang.String TEXT_FIELD_TRAILING_ICON = "JTextField.trailingIcon"
 fld public final static java.lang.String TITLE_BAR_BACKGROUND = "JRootPane.titleBarBackground"
 fld public final static java.lang.String TITLE_BAR_FOREGROUND = "JRootPane.titleBarForeground"
+fld public final static java.lang.String TITLE_BAR_HEIGHT = "JRootPane.titleBarHeight"
 fld public final static java.lang.String TITLE_BAR_SHOW_CLOSE = "JRootPane.titleBarShowClose"
 fld public final static java.lang.String TITLE_BAR_SHOW_ICON = "JRootPane.titleBarShowIcon"
 fld public final static java.lang.String TITLE_BAR_SHOW_ICONIFFY = "JRootPane.titleBarShowIconify"
@@ -223,6 +224,7 @@ meth public static java.util.Map<java.lang.String,java.lang.Class<?>> getStyleab
 meth public static java.util.Map<java.lang.String,java.lang.String> getGlobalExtraDefaults()
 meth public static java.util.function.Function<java.lang.String,java.awt.Color> getSystemColorGetter()
 meth public static javax.swing.UIDefaults$ActiveValue createActiveFontValue(float)
+meth public static void disableWindowsD3Donscreen()
 meth public static void hideMnemonics()
 meth public static void initIconColors(javax.swing.UIDefaults,boolean)
 meth public static void installLafInfo(java.lang.String,java.lang.Class<? extends javax.swing.LookAndFeel>)
@@ -296,6 +298,8 @@ fld public final static java.lang.String UPDATE_UI_ON_SYSTEM_FONT_CHANGE = "flat
 fld public final static java.lang.String USE_JETBRAINS_CUSTOM_DECORATIONS = "flatlaf.useJetBrainsCustomDecorations"
  anno 0 java.lang.Deprecated()
 fld public final static java.lang.String USE_NATIVE_LIBRARY = "flatlaf.useNativeLibrary"
+fld public final static java.lang.String USE_ROUNDED_POPUP_BORDER = "flatlaf.useRoundedPopupBorder"
+fld public final static java.lang.String USE_SUB_MENU_SAFE_TRIANGLE = "flatlaf.useSubMenuSafeTriangle"
 fld public final static java.lang.String USE_TEXT_Y_CORRECTION = "flatlaf.useTextYCorrection"
 fld public final static java.lang.String USE_UBUNTU_FONT = "flatlaf.useUbuntuFont"
 fld public final static java.lang.String USE_WINDOW_DECORATIONS = "flatlaf.useWindowDecorations"
@@ -629,16 +633,33 @@ hfds alpha,hsl,rgb
 
 CLSS public com.formdev.flatlaf.util.HiDPIUtils
 cons public init()
+innr public abstract interface static DirtyRegionCallback
 innr public abstract interface static Painter
+innr public static HiDPIRepaintManager
 meth public static float computeTextYCorrection(java.awt.Graphics2D)
 meth public static java.awt.Graphics2D createGraphicsTextYCorrection(java.awt.Graphics2D)
+meth public static void addDirtyRegion(javax.swing.JComponent,int,int,int,int,com.formdev.flatlaf.util.HiDPIUtils$DirtyRegionCallback)
 meth public static void drawStringUnderlineCharAtWithYCorrection(javax.swing.JComponent,java.awt.Graphics2D,java.lang.String,int,int,int)
 meth public static void drawStringWithYCorrection(javax.swing.JComponent,java.awt.Graphics2D,java.lang.String,int,int)
+meth public static void installHiDPIRepaintManager()
 meth public static void paintAtScale1x(java.awt.Graphics2D,int,int,int,int,com.formdev.flatlaf.util.HiDPIUtils$Painter)
 meth public static void paintAtScale1x(java.awt.Graphics2D,javax.swing.JComponent,com.formdev.flatlaf.util.HiDPIUtils$Painter)
+meth public static void repaint(java.awt.Component)
+meth public static void repaint(java.awt.Component,int,int,int,int)
+meth public static void repaint(java.awt.Component,java.awt.Rectangle)
 supr java.lang.Object
 hfds CORRECTION_INTER,CORRECTION_OPEN_SANS,CORRECTION_SEGOE_UI,CORRECTION_TAHOMA,SCALE_FACTORS,useDebugScaleFactor,useTextYCorrection
 
+CLSS public abstract interface static com.formdev.flatlaf.util.HiDPIUtils$DirtyRegionCallback
+ outer com.formdev.flatlaf.util.HiDPIUtils
+meth public abstract void addDirtyRegion(javax.swing.JComponent,int,int,int,int)
+
+CLSS public static com.formdev.flatlaf.util.HiDPIUtils$HiDPIRepaintManager
+ outer com.formdev.flatlaf.util.HiDPIUtils
+cons public init()
+meth public void addDirtyRegion(javax.swing.JComponent,int,int,int,int)
+supr javax.swing.RepaintManager
+
 CLSS public abstract interface static com.formdev.flatlaf.util.HiDPIUtils$Painter
  outer com.formdev.flatlaf.util.HiDPIUtils
 meth public abstract void paint(java.awt.Graphics2D,int,int,int,int,double)
@@ -1137,6 +1158,31 @@ meth public void provideErrorFeedback(java.awt.Component)
 meth public void uninitialize()
 supr java.lang.Object
 
+CLSS public javax.swing.RepaintManager
+cons public init()
+meth public boolean isCompletelyDirty(javax.swing.JComponent)
+meth public boolean isDoubleBufferingEnabled()
+meth public java.awt.Dimension getDoubleBufferMaximumSize()
+meth public java.awt.Image getOffscreenBuffer(java.awt.Component,int,int)
+meth public java.awt.Image getVolatileOffscreenBuffer(java.awt.Component,int,int)
+meth public java.awt.Rectangle getDirtyRegion(javax.swing.JComponent)
+meth public java.lang.String toString()
+meth public static javax.swing.RepaintManager currentManager(java.awt.Component)
+meth public static javax.swing.RepaintManager currentManager(javax.swing.JComponent)
+meth public static void setCurrentManager(javax.swing.RepaintManager)
+meth public void addDirtyRegion(java.applet.Applet,int,int,int,int)
+meth public void addDirtyRegion(java.awt.Window,int,int,int,int)
+meth public void addDirtyRegion(javax.swing.JComponent,int,int,int,int)
+meth public void addInvalidComponent(javax.swing.JComponent)
+meth public void markCompletelyClean(javax.swing.JComponent)
+meth public void markCompletelyDirty(javax.swing.JComponent)
+meth public void paintDirtyRegions()
+meth public void removeInvalidComponent(javax.swing.JComponent)
+meth public void setDoubleBufferMaximumSize(java.awt.Dimension)
+meth public void setDoubleBufferingEnabled(boolean)
+meth public void validateInvalidComponents()
+supr java.lang.Object
+
 CLSS public abstract javax.swing.border.AbstractBorder
 cons public init()
 intf java.io.Serializable

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatClientProperties.java

@@ -102,6 +102,17 @@ public interface FlatClientProperties
 	 */
 	String BUTTON_TYPE_BORDERLESS = "borderless";
 
+	/**
+	 * Specifies whether the button preferred size will be made square (quadratically).
+	 * <p>
+	 * <strong>Components</strong> {@link javax.swing.JButton} and {@link javax.swing.JToggleButton}<br>
+	 * <strong>Value type</strong> {@link java.lang.Boolean}
+	 */
+	String SQUARE_SIZE = "JButton.squareSize";
+
+
+	//---- JCheckBox ----------------------------------------------------------
+
 	/**
 	 * Specifies selected state of a checkbox.
 	 * <p>
@@ -118,14 +129,6 @@ public interface FlatClientProperties
 	 */
 	String SELECTED_STATE_INDETERMINATE = "indeterminate";
 
-	/**
-	 * Specifies whether the button preferred size will be made square (quadratically).
-	 * <p>
-	 * <strong>Components</strong> {@link javax.swing.JButton} and {@link javax.swing.JToggleButton}<br>
-	 * <strong>Value type</strong> {@link java.lang.Boolean}
-	 */
-	String SQUARE_SIZE = "JButton.squareSize";
-
 
 	//---- JComponent ---------------------------------------------------------
 
@@ -458,7 +461,7 @@ public interface FlatClientProperties
 	 * {@link FlatSystemProperties#USE_WINDOW_DECORATIONS}, but higher priority
 	 * than UI default {@code TitlePane.useWindowDecorations}.
 	 * <p>
-	 * (requires Window 10)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
@@ -478,7 +481,7 @@ public interface FlatClientProperties
 	 * {@link FlatSystemProperties#MENUBAR_EMBEDDED}, but higher priority
 	 * than UI default {@code TitlePane.menuBarEmbedded}.
 	 * <p>
-	 * (requires Window 10)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
@@ -504,6 +507,8 @@ public interface FlatClientProperties
 	 * The user can left-click-and-drag on the title bar area to move the window,
 	 * except when clicking on a component that processes mouse events (e.g. buttons or menus).
 	 * <p>
+	 * (requires Windows 10/11)
+	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
 	 *
@@ -534,7 +539,7 @@ public interface FlatClientProperties
 	 * <p>
 	 * This client property has higher priority than UI default {@code TitlePane.showIcon}.
 	 * <p>
-	 * (requires Window 10)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
@@ -550,6 +555,8 @@ public interface FlatClientProperties
 	 * Setting this shows/hides the windows title
 	 * for the {@code JFrame} or {@code JDialog} that contains the root pane.
 	 * <p>
+	 * (requires Windows 10/11)
+	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
 	 *
@@ -564,6 +571,8 @@ public interface FlatClientProperties
 	 * Setting this shows/hides the "iconify" button
 	 * for the {@code JFrame} that contains the root pane.
 	 * <p>
+	 * (requires Windows 10/11)
+	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
 	 *
@@ -578,6 +587,8 @@ public interface FlatClientProperties
 	 * Setting this shows/hides the "maximize/restore" button
 	 * for the {@code JFrame} that contains the root pane.
 	 * <p>
+	 * (requires Windows 10/11)
+	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
 	 *
@@ -592,6 +603,8 @@ public interface FlatClientProperties
 	 * Setting this shows/hides the "close" button
 	 * for the {@code JFrame} or {@code JDialog} that contains the root pane.
 	 * <p>
+	 * (requires Windows 10/11)
+	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
 	 *
@@ -602,7 +615,7 @@ public interface FlatClientProperties
 	/**
 	 * Background color of window title bar (requires enabled window decorations).
 	 * <p>
-	 * (requires Window 10)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.awt.Color}
@@ -614,7 +627,7 @@ public interface FlatClientProperties
 	/**
 	 * Foreground color of window title bar (requires enabled window decorations).
 	 * <p>
-	 * (requires Window 10)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.awt.Color}
@@ -623,10 +636,24 @@ public interface FlatClientProperties
 	 */
 	String TITLE_BAR_FOREGROUND = "JRootPane.titleBarForeground";
 
+	/**
+	 * Specifies the preferred height of title bar (requires enabled window decorations).
+	 * <p>
+	 * (requires Windows 10/11)
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
+	 * <strong>Value type</strong> {@link java.lang.Integer}
+	 *
+	 * @since 3.5.2
+	 */
+	String TITLE_BAR_HEIGHT = "JRootPane.titleBarHeight";
+
 	/**
 	 * Specifies whether the glass pane should have full height and overlap the title bar,
 	 * if FlatLaf window decorations are enabled. Default is {@code false}.
 	 * <p>
+	 * (requires Windows 10/11)
+	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Boolean}
 	 *
@@ -984,7 +1011,7 @@ public interface FlatClientProperties
 	 * <strong>Component</strong> {@link javax.swing.JTabbedPane}<br>
 	 * <strong>Value type</strong> {@link java.lang.Integer} or {@link java.lang.String}<br>
 	 * <strong>Allowed Values</strong>
-	 *     {@link SwingConstants#LEADING} (default)
+	 *     {@link SwingConstants#LEADING} (default),
 	 *     {@link SwingConstants#TRAILING},
 	 *     {@link SwingConstants#CENTER},
 	 *     {@link #TABBED_PANE_ALIGN_LEADING} (default),
@@ -1096,7 +1123,7 @@ public interface FlatClientProperties
 	 * <strong>Allowed Values</strong>
 	 *     {@link SwingConstants#LEFT},
 	 *     {@link SwingConstants#RIGHT},
-	 *     {@link #TABBED_PANE_TAB_ROTATION_NONE}, (default)
+	 *     {@link #TABBED_PANE_TAB_ROTATION_NONE} (default),
 	 *     {@link #TABBED_PANE_TAB_ROTATION_AUTO},
 	 *     {@link #TABBED_PANE_TAB_ROTATION_LEFT} or
 	 *     {@link #TABBED_PANE_TAB_ROTATION_RIGHT}
@@ -1345,8 +1372,8 @@ public interface FlatClientProperties
 	 * <p>
 	 * <strong>Component</strong> {@link javax.swing.JToggleButton}<br>
 	 * <strong>Value type</strong> {@link java.lang.Integer}<br>
-	 * <strong>SupportedValues:</strong>
-	 *     {@link SwingConstants#BOTTOM} (default)
+	 * <strong>Allowed Values</strong>
+	 *     {@link SwingConstants#BOTTOM} (default),
 	 *     {@link SwingConstants#TOP},
 	 *     {@link SwingConstants#LEFT} or
 	 *     {@link SwingConstants#RIGHT}

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatDefaultsAddon.java

@@ -48,7 +48,7 @@ public abstract class FlatDefaultsAddon
 	public InputStream getDefaults( Class<?> lafClass ) {
 		Class<?> addonClass = this.getClass();
 		String propertiesName = '/' + addonClass.getPackage().getName().replace( '.', '/' )
-			+ '/' + lafClass.getSimpleName() + ".properties";
+			+ '/' + UIDefaultsLoader.simpleClassName( lafClass ) + ".properties";
 		return addonClass.getResourceAsStream( propertiesName );
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java

@@ -20,6 +20,7 @@ import java.awt.Color;
 import java.awt.Component;
 import java.awt.EventQueue;
 import java.awt.Font;
+import java.awt.GraphicsEnvironment;
 import java.awt.Image;
 import java.awt.RenderingHints;
 import java.awt.Toolkit;
@@ -119,6 +120,46 @@ public abstract class FlatLaf
 	private static String preferredSemiboldFontFamily;
 	private static String preferredMonospacedFontFamily;
 
+	static {
+		// see disableWindowsD3Donscreen() for details
+		// https://github.com/JFormDesigner/FlatLaf/issues/887
+		if( SystemInfo.isWindows &&
+			System.getProperty( "sun.java2d.d3d.onscreen" ) == null &&
+			System.getProperty( "sun.java2d.d3d" ) == null &&
+			System.getProperty( "sun.java2d.noddraw" ) == null )
+		  System.setProperty( "sun.java2d.d3d.onscreen", "false" );
+	}
+
+	/**
+	 * Disable usage of Windows Direct3D (DirectX) onscreen surfaces because this may lead to
+	 * repaint issues (ghosting) on some systems (probably depending on graphics card/driver).
+	 * Problem occurs usually when a small heavy-weight popup window (menu, combobox, tooltip) is shown.
+	 * <p>
+	 * Sets system property {@code sun.java2d.d3d.onscreen} to {@code false},
+	 * but only if {@code sun.java2d.d3d.onscreen}, {@code sun.java2d.d3d}
+	 * and {@code sun.java2d.noddraw} are not yet set.
+	 * <p>
+	 * <strong>Note</strong>: Must be invoked very early before the graphics environment is created.
+	 * <p>
+	 * This method is automatically invoked when loading this class,
+	 * which is usually before the graphics environment is created.
+	 * E.g. when doing {@code FlatLightLaf.setup()} or
+	 * {@code UIManager.setLookAndFeel( "com.formdev.flatlaf.FlatLightLaf" )}.
+	 * <p>
+	 * However, it may be invoked too late if you use some methods from {@link UIManager}
+	 * of {@link GraphicsEnvironment} before setting look and feel.
+	 * E.g. {@link UIManager#put(Object, Object)}.
+	 * In that case invoke this method yourself very early.
+	 * <p>
+	 * <strong>Tip</strong>: How to find out when the graphics environment is created?
+	 * Set a breakpoint at constructor of class {@link GraphicsEnvironment} and look at the stack.
+	 *
+	 * @since 3.5.2
+	 */
+	public static void disableWindowsD3Donscreen() {
+		// dummy method used to trigger invocation of "static {...}" block
+	}
+
 	/**
 	 * Sets the application look and feel to the given LaF
 	 * using {@link UIManager#setLookAndFeel(javax.swing.LookAndFeel)}.

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatSystemProperties.java

@@ -82,7 +82,7 @@ public interface FlatSystemProperties
 	 * {@link FlatClientProperties#USE_WINDOW_DECORATIONS} and
 	 * UI default {@code TitlePane.useWindowDecorations}.
 	 * <p>
-	 * (requires Window 10/11)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Allowed Values</strong> {@code false} and {@code true}<br>
 	 * <strong>Default</strong> none
@@ -99,7 +99,7 @@ public interface FlatSystemProperties
 	 * Setting this to {@code false} disables using JetBrains Runtime custom window decorations.
 	 * Then FlatLaf native window decorations are used.
 	 * <p>
-	 * (requires Window 10/11)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Allowed Values</strong> {@code false} and {@code true}<br>
 	 * <strong>Default</strong> {@code false} (since v2; was {@code true} in v1)
@@ -120,7 +120,7 @@ public interface FlatSystemProperties
 	 * {@link FlatClientProperties#MENU_BAR_EMBEDDED} and
 	 * UI default {@code TitlePane.menuBarEmbedded}.
 	 * <p>
-	 * (requires Window 10/11)
+	 * (requires Windows 10/11)
 	 * <p>
 	 * <strong>Allowed Values</strong> {@code false} and {@code true}<br>
 	 * <strong>Default</strong> none
@@ -135,6 +135,18 @@ public interface FlatSystemProperties
 	 */
 	String ANIMATION = "flatlaf.animation";
 
+	/**
+	 * Specifies whether native rounded popup borders should be used (if supported by operating system).
+	 * <p>
+	 * (requires Window 11 or macOS)
+	 * <p>
+	 * <strong>Allowed Values</strong> {@code false} and {@code true}<br>
+	 * <strong>Default</strong> {@code true}; except on macOS 14.4+ where it is {@code false}
+	 *
+	 * @since 3.5.2
+	 */
+	String USE_ROUNDED_POPUP_BORDER = "flatlaf.useRoundedPopupBorder";
+
 	/**
 	 * Specifies whether vertical text position is corrected when UI is scaled on HiDPI screens.
 	 * <p>
@@ -204,6 +216,16 @@ public interface FlatSystemProperties
 	 */
 	String NATIVE_LIBRARY_PATH = "flatlaf.nativeLibraryPath";
 
+	/**
+	 * Specifies whether safe triangle is used to improve usability of submenus.
+	 * <p>
+	 * <strong>Allowed Values</strong> {@code false} and {@code true}<br>
+	 * <strong>Default</strong> {@code true}
+	 *
+	 * @since 3.5.1
+	 */
+	String USE_SUB_MENU_SAFE_TRIANGLE = "flatlaf.useSubMenuSafeTriangle";
+
 	/**
 	 * Checks whether a system property is set and returns {@code true} if its value
 	 * is {@code "true"} (case-insensitive), otherwise it returns {@code false}.

flatlaf-core/src/main/java/com/formdev/flatlaf/SubMenuUsabilityHelper.java

@@ -45,6 +45,7 @@ import javax.swing.UIManager;
 import javax.swing.event.ChangeEvent;
 import javax.swing.event.ChangeListener;
 import com.formdev.flatlaf.ui.FlatUIUtils;
+import com.formdev.flatlaf.util.LoggingFacade;
 
 /**
  * Improves usability of submenus by using a
@@ -64,6 +65,7 @@ class SubMenuUsabilityHelper
 	// https://github.com/apache/netbeans/issues/4231#issuecomment-1179616607
 	private static SubMenuUsabilityHelper instance;
 
+	private boolean eventQueuePushNotSupported;
 	private SubMenuEventQueue subMenuEventQueue;
 	private SafeTrianglePainter safeTrianglePainter;
 	private boolean changePending;
@@ -83,6 +85,9 @@ class SubMenuUsabilityHelper
 		if( instance != null )
 			return false;
 
+		if( !FlatSystemProperties.getBoolean( FlatSystemProperties.USE_SUB_MENU_SAFE_TRIANGLE, true ) )
+			return false;
+
 		instance = new SubMenuUsabilityHelper();
 		MenuSelectionManager.defaultManager().addChangeListener( instance );
 		return true;
@@ -99,7 +104,7 @@ class SubMenuUsabilityHelper
 
 	@Override
 	public void stateChanged( ChangeEvent e ) {
-		if( !FlatUIUtils.getUIBoolean( KEY_USE_SAFE_TRIANGLE, true ))
+		if( eventQueuePushNotSupported || !FlatUIUtils.getUIBoolean( KEY_USE_SAFE_TRIANGLE, true ))
 			return;
 
 		// handle menu selection change later, but only once in case of temporary changes
@@ -173,8 +178,29 @@ debug*/
 		targetBottomY = popupLocation.y + popupSize.height;
 
 		// install own event queue to suppress mouse events when mouse is moved within safe triangle
-		if( subMenuEventQueue == null )
-			subMenuEventQueue = new SubMenuEventQueue();
+		if( subMenuEventQueue == null ) {
+			SubMenuEventQueue queue = new SubMenuEventQueue();
+
+			try {
+				Toolkit toolkit = Toolkit.getDefaultToolkit();
+				toolkit.getSystemEventQueue().push( queue );
+
+				// check whether push() worked
+				// (e.g. SWTSwing uses own event queue that does not support push())
+				if( toolkit.getSystemEventQueue() != queue ) {
+					eventQueuePushNotSupported = true;
+					LoggingFacade.INSTANCE.logSevere( "FlatLaf: Failed to push submenu event queue. Disabling submenu safe triangle.", null );
+					return;
+				}
+
+				subMenuEventQueue = queue;
+			} catch( RuntimeException ex ) {
+				// catch runtime exception from EventQueue.push()
+				eventQueuePushNotSupported = true;
+				LoggingFacade.INSTANCE.logSevere( "FlatLaf: Failed to push submenu event queue. Disabling submenu safe triangle.", ex );
+				return;
+			}
+		}
 
 		// create safe triangle painter
 		if( safeTrianglePainter == null && UIManager.getBoolean( KEY_SHOW_SAFE_TRIANGLE ) )
@@ -247,8 +273,6 @@ debug*/
 				}
 			} );
 			timeoutTimer.setRepeats( false );
-
-			Toolkit.getDefaultToolkit().getSystemEventQueue().push( this );
 		}
 
 		void uninstall() {

flatlaf-core/src/main/java/com/formdev/flatlaf/UIDefaultsLoader.java

@@ -161,7 +161,7 @@ class UIDefaultsLoader
 						classLoader = FlatLaf.class.getClassLoader();
 
 					for( Class<?> lafClass : lafClasses ) {
-						String propertiesName = packageName + '/' + lafClass.getSimpleName() + ".properties";
+						String propertiesName = packageName + '/' + simpleClassName( lafClass ) + ".properties";
 						try( InputStream in = classLoader.getResourceAsStream( propertiesName ) ) {
 							if( in != null )
 								properties.load( in );
@@ -171,7 +171,7 @@ class UIDefaultsLoader
 					// load from package URL
 					URL packageUrl = (URL) source;
 					for( Class<?> lafClass : lafClasses ) {
-						URL propertiesUrl = new URL( packageUrl + lafClass.getSimpleName() + ".properties" );
+						URL propertiesUrl = new URL( packageUrl + simpleClassName( lafClass ) + ".properties" );
 
 						try( InputStream in = propertiesUrl.openStream() ) {
 							properties.load( in );
@@ -183,7 +183,7 @@ class UIDefaultsLoader
 					// load from folder
 					File folder = (File) source;
 					for( Class<?> lafClass : lafClasses ) {
-						File propertiesFile = new File( folder, lafClass.getSimpleName() + ".properties" );
+						File propertiesFile = new File( folder, simpleClassName( lafClass ) + ".properties" );
 						if( !propertiesFile.isFile() )
 							continue;
 
@@ -294,6 +294,14 @@ class UIDefaultsLoader
 		}
 	}
 
+	/**
+	 * Similar to Class.getSimpleName(), but includes enclosing class for nested classes.
+	 */
+	static String simpleClassName( Class<?> cls ) {
+		String className = cls.getName();
+		return className.substring( className.lastIndexOf( '.' ) + 1 );
+	}
+
 	static void logParseError( String key, String value, RuntimeException ex, boolean severe ) {
 		String message = "FlatLaf: Failed to parse: '" + key + '=' + value + '\'';
 		if( severe )
@@ -630,14 +638,18 @@ class UIDefaultsLoader
 			// Syntax: top,left,bottom,right[,lineColor[,lineThickness[,arc]]]
 			List<String> parts = splitFunctionParams( value, ',' );
 			Insets insets = parseInsets( value );
-			ColorUIResource lineColor = (parts.size() >= 5)
+			ColorUIResource lineColor = (parts.size() >= 5 && !parts.get( 4 ).isEmpty())
 				? (ColorUIResource) parseColorOrFunction( resolver.apply( parts.get( 4 ) ), resolver )
 				: null;
-			float lineThickness = (parts.size() >= 6 && !parts.get( 5 ).isEmpty()) ? parseFloat( parts.get( 5 ) ) : 1f;
-			int arc = (parts.size() >= 7) ? parseInteger( parts.get( 6 ) ) : 0;
+			float lineThickness = (parts.size() >= 6 && !parts.get( 5 ).isEmpty())
+				? parseFloat( parts.get( 5 ) )
+				: 1f;
+			int arc = (parts.size() >= 7) && !parts.get( 6 ).isEmpty()
+				? parseInteger( parts.get( 6 ) )
+				: -1;
 
 			return (LazyValue) t -> {
-				return (lineColor != null)
+				return (lineColor != null || arc > 0)
 					? new FlatLineBorder( insets, lineColor, lineThickness, arc )
 					: new FlatEmptyBorder( insets );
 			};

flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatAbstractIcon.java

@@ -57,6 +57,8 @@ public abstract class FlatAbstractIcon
 //			g2.setColor( Color.blue );
 //			g2.drawRect( x, y, getIconWidth() - 1, getIconHeight() - 1 );
 
+			paintBackground( c, g2, x, y );
+
 			g2.translate( x, y );
 			UIScale.scaleGraphics( g2 );
 
@@ -69,7 +71,11 @@ public abstract class FlatAbstractIcon
 		}
 	}
 
-	protected abstract void paintIcon( Component c, Graphics2D g2 );
+	/** @since 3.5.2 */
+	protected void paintBackground( Component c, Graphics2D g, int x, int y ) {
+	}
+
+	protected abstract void paintIcon( Component c, Graphics2D g );
 
 	@Override
 	public int getIconWidth() {

flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatWindowAbstractIcon.java

@@ -60,23 +60,24 @@ public abstract class FlatWindowAbstractIcon
 
 	@Override
 	protected void paintIcon( Component c, Graphics2D g ) {
-		paintBackground( c, g );
-
 		g.setColor( getForeground( c ) );
 		HiDPIUtils.paintAtScale1x( g, 0, 0, width, height, this::paintIconAt1x );
 	}
 
 	protected abstract void paintIconAt1x( Graphics2D g, int x, int y, int width, int height, double scaleFactor );
 
-	protected void paintBackground( Component c, Graphics2D g ) {
+	/** @since 3.5.2 */
+	@Override
+	protected void paintBackground( Component c, Graphics2D g, int x, int y ) {
 		Color background = FlatButtonUI.buttonStateColor( c, null, null, null, hoverBackground, pressedBackground );
 		if( background != null ) {
 			// disable antialiasing for background rectangle painting to avoid blurry edges when scaled (e.g. at 125% or 175%)
 			Object oldHint = g.getRenderingHint( RenderingHints.KEY_ANTIALIASING );
 			g.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF );
 
+			// fill background of whole component
 			g.setColor( FlatUIUtils.deriveColor( background, c.getBackground() ) );
-			g.fillRect( 0, 0, width, height );
+			g.fillRect( 0, 0, c.getWidth(), c.getHeight() );
 
 			g.setRenderingHint( RenderingHints.KEY_ANTIALIASING, oldHint );
 		}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatBorder.java

@@ -135,7 +135,7 @@ public class FlatBorder
 			Paint borderColor = (outlineColor != null) ? outlineColor : getBorderColor( c );
 			FlatUIUtils.paintOutlinedComponent( g2, x, y, width, height,
 				focusWidth, 1, focusInnerWidth, borderWidth, arc,
-				focusColor, borderColor, null );
+				focusColor, borderColor, null, c instanceof JScrollPane );
 		} finally {
 			g2.dispose();
 		}
@@ -277,7 +277,7 @@ public class FlatBorder
 	}
 
 	/**
-	 * Returns the (unscaled) arc diameter of the border.
+	 * Returns the (unscaled) arc diameter of the border corners.
 	 */
 	protected int getArc( Component c ) {
 		return 0;

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonBorder.java

@@ -42,6 +42,13 @@ import com.formdev.flatlaf.util.UIScale;
  * @uiDefault Button.disabledBorderColor		Color
  * @uiDefault Button.focusedBorderColor			Color
  * @uiDefault Button.hoverBorderColor			Color	optional
+ * @uiDefault Button.pressedBorderColor			Color	optional
+ *
+ * @uiDefault Button.selectedBorderColor		Color	optional
+ * @uiDefault Button.disabledSelectedBorderColor Color	optional
+ * @uiDefault Button.focusedSelectedBorderColor	Color	optional
+ * @uiDefault Button.hoverSelectedBorderColor	Color	optional
+ * @uiDefault Button.pressedSelectedBorderColor	Color	optional
  *
  * @uiDefault Button.default.borderWidth		int or float
  * @uiDefault Button.default.borderColor		Color
@@ -49,6 +56,7 @@ import com.formdev.flatlaf.util.UIScale;
  * @uiDefault Button.default.endBorderColor		Color	optional; if set, a gradient paint is used
  * @uiDefault Button.default.focusedBorderColor	Color
  * @uiDefault Button.default.focusColor			Color
+ * @uiDefault Button.default.pressedBorderColor	Color	optional
  * @uiDefault Button.default.hoverBorderColor	Color	optional
  *
  * @uiDefault Button.toolbar.focusWidth			int or float		optional; default is 1.5
@@ -65,6 +73,13 @@ public class FlatButtonBorder
 
 	protected Color endBorderColor = UIManager.getColor( "Button.endBorderColor" );
 	@Styleable protected Color hoverBorderColor = UIManager.getColor( "Button.hoverBorderColor" );
+	/** @since 3.5 */ @Styleable protected Color pressedBorderColor = UIManager.getColor( "Button.pressedBorderColor" );
+
+	/** @since 3.5 */ @Styleable protected Color selectedBorderColor = UIManager.getColor( "Button.selectedBorderColor" );
+	/** @since 3.5 */ @Styleable protected Color disabledSelectedBorderColor = UIManager.getColor( "Button.disabledSelectedBorderColor" );
+	/** @since 3.5 */ @Styleable protected Color focusedSelectedBorderColor = UIManager.getColor( "Button.focusedSelectedBorderColor" );
+	/** @since 3.5 */ @Styleable protected Color hoverSelectedBorderColor = UIManager.getColor( "Button.hoverSelectedBorderColor" );
+	/** @since 3.5 */ @Styleable protected Color pressedSelectedBorderColor = UIManager.getColor( "Button.pressedSelectedBorderColor" );
 
 	@Styleable(dot=true) protected float defaultBorderWidth = FlatUIUtils.getUIFloat( "Button.default.borderWidth", 1 );
 	@Styleable(dot=true) protected Color defaultBorderColor = FlatUIUtils.getUIColor( "Button.default.startBorderColor", "Button.default.borderColor" );
@@ -72,6 +87,7 @@ public class FlatButtonBorder
 	@Styleable(dot=true) protected Color defaultFocusedBorderColor = UIManager.getColor( "Button.default.focusedBorderColor" );
 	@Styleable(dot=true) protected Color defaultFocusColor = UIManager.getColor( "Button.default.focusColor" );
 	@Styleable(dot=true) protected Color defaultHoverBorderColor = UIManager.getColor( "Button.default.hoverBorderColor" );
+	/** @since 3.5 */ @Styleable(dot=true) protected Color defaultPressedBorderColor = UIManager.getColor( "Button.default.pressedBorderColor" );
 
 	/** @since 1.4 */ @Styleable(dot=true) protected float toolbarFocusWidth = FlatUIUtils.getUIFloat( "Button.toolbar.focusWidth", 1.5f );
 	/** @since 1.4 */ @Styleable(dot=true) protected Color toolbarFocusColor = UIManager.getColor( "Button.toolbar.focusColor" );
@@ -139,12 +155,13 @@ public class FlatButtonBorder
 	@Override
 	protected Paint getBorderColor( Component c ) {
 		boolean def = FlatButtonUI.isDefaultButton( c );
+		boolean selected = (c instanceof AbstractButton && ((AbstractButton)c).isSelected());
 		Paint color = FlatButtonUI.buttonStateColor( c,
-			def ? defaultBorderColor : borderColor,
-			disabledBorderColor,
-			def ? defaultFocusedBorderColor : focusedBorderColor,
-			def ? defaultHoverBorderColor : hoverBorderColor,
-			null );
+			def ? defaultBorderColor : ((selected && selectedBorderColor != null) ? selectedBorderColor : borderColor),
+			(selected && disabledSelectedBorderColor != null) ? disabledSelectedBorderColor : disabledBorderColor,
+			def ? defaultFocusedBorderColor : ((selected && focusedSelectedBorderColor != null) ? focusedSelectedBorderColor : focusedBorderColor),
+			def ? defaultHoverBorderColor : ((selected && hoverSelectedBorderColor != null) ? hoverSelectedBorderColor : hoverBorderColor),
+			def ? defaultPressedBorderColor : ((selected && pressedSelectedBorderColor != null) ? pressedSelectedBorderColor : pressedBorderColor) );
 
 		// change to gradient paint if start/end colors are specified
 		Color startBg = def ? defaultBorderColor : borderColor;

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonUI.java

@@ -29,6 +29,7 @@ import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
 import java.awt.Rectangle;
+import java.awt.event.FocusEvent;
 import java.awt.geom.RoundRectangle2D;
 import java.beans.PropertyChangeEvent;
 import java.util.Map;
@@ -61,6 +62,7 @@ import com.formdev.flatlaf.icons.FlatHelpButtonIcon;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.ui.FlatStylingSupport.UnknownStyleException;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -300,6 +302,10 @@ public class FlatButtonUI
 
 	protected void propertyChange( AbstractButton b, PropertyChangeEvent e ) {
 		switch( e.getPropertyName() ) {
+			case BasicHTML.propertyKey:
+				FlatHTML.updateRendererCSSFontBaseSize( b );
+				break;
+
 			case SQUARE_SIZE:
 			case MINIMUM_WIDTH:
 			case MINIMUM_HEIGHT:
@@ -308,11 +314,11 @@ public class FlatButtonUI
 
 			case BUTTON_TYPE:
 				b.revalidate();
-				b.repaint();
+				HiDPIUtils.repaint( b );
 				break;
 
 			case OUTLINE:
-				b.repaint();
+				HiDPIUtils.repaint( b );
 				break;
 
 			case STYLE:
@@ -324,7 +330,7 @@ public class FlatButtonUI
 				} else
 					installStyle( b );
 				b.revalidate();
-				b.repaint();
+				HiDPIUtils.repaint( b );
 				break;
 		}
 	}
@@ -583,9 +589,16 @@ public class FlatButtonUI
 		// paint text
 		if( clippedText != null && !clippedText.isEmpty() ) {
 			View view = (View) b.getClientProperty( BasicHTML.propertyKey );
-			if( view != null )
+			if( view != null ) {
+				// update foreground color in HTML view, which is necessary
+				// for selected and pressed states
+				// (only for enabled buttons, because UIManager.getColor("textInactiveText")
+				// is used for disabled components; see: javax.swing.text.GlyphView.paint())
+				if( b.isEnabled() )
+					FlatHTML.updateRendererCSSForeground( view, getForeground( b ) );
+
 				view.paint( g, textR ); // HTML text
-			else
+			} else
 				paintText( g, b, textR, clippedText );
 		}
 
@@ -631,8 +644,6 @@ public class FlatButtonUI
 	}
 
 	public static void paintText( Graphics g, AbstractButton b, Rectangle textRect, String text, Color foreground ) {
-		if(foreground == null)
-			foreground=Color.red;
 		FontMetrics fm = b.getFontMetrics( b.getFont() );
 		int mnemonicIndex = FlatLaf.isShowMnemonics() ? b.getDisplayedMnemonicIndex() : -1;
 
@@ -906,7 +917,7 @@ public class FlatButtonUI
 
 		@Override
 		public void stateChanged( ChangeEvent e ) {
-			super.stateChanged( e );
+			HiDPIUtils.repaint( b );
 
 			// if button is in toolbar, repaint button groups
 			AbstractButton b = (AbstractButton) e.getSource();
@@ -918,5 +929,17 @@ public class FlatButtonUI
 					((FlatToolBarUI)ui).repaintButtonGroup( b );
 			}
 		}
+
+		@Override
+		public void focusGained( FocusEvent e ) {
+			super.focusGained( e );
+			HiDPIUtils.repaint( b );
+		}
+
+		@Override
+		public void focusLost( FocusEvent e ) {
+			super.focusLost( e );
+			HiDPIUtils.repaint( b );
+		}
 	}
 }

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatCheckBoxMenuItemUI.java

@@ -23,6 +23,7 @@ import java.lang.invoke.MethodHandles;
 import java.util.Map;
 import javax.swing.Icon;
 import javax.swing.JComponent;
+import javax.swing.JMenuItem;
 import javax.swing.LookAndFeel;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicCheckBoxMenuItemUI;
@@ -102,13 +103,23 @@ public class FlatCheckBoxMenuItemUI
 		oldStyleValues = null;
 	}
 
+	@Override
+	protected void installComponents( JMenuItem menuItem ) {
+		super.installComponents( menuItem );
+
+		// update HTML renderer if necessary
+		FlatHTML.updateRendererCSSFontBaseSize( menuItem );
+	}
+
 	protected FlatMenuItemRenderer createRenderer() {
 		return new FlatMenuItemRenderer( menuItem, checkIcon, arrowIcon, acceleratorFont, acceleratorDelimiter );
 	}
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+		return FlatHTML.createPropertyChangeListener(
+			FlatStylingSupport.createPropertyChangeListener( c, this::installStyle,
+				super.createPropertyChangeListener( c ) ) );
 	}
 
 	/** @since 2 */

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java

@@ -78,6 +78,7 @@ import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableField;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableLookupProvider;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.SystemInfo;
 
@@ -220,7 +221,7 @@ public class FlatComboBoxUI
 
 			private void repaintArrowButton() {
 				if( arrowButton != null && !comboBox.isEditable() )
-					arrowButton.repaint();
+					HiDPIUtils.repaint( arrowButton );
 			}
 		};
 		comboBox.addMouseListener( hoverListener );
@@ -351,15 +352,15 @@ public class FlatComboBoxUI
 			@Override
 			public void focusGained( FocusEvent e ) {
 				super.focusGained( e );
-				if( comboBox != null && comboBox.isEditable() )
-					comboBox.repaint();
+				if( comboBox != null )
+					HiDPIUtils.repaint( comboBox );
 			}
 
 			@Override
 			public void focusLost( FocusEvent e ) {
 				super.focusLost( e );
-				if( comboBox != null && comboBox.isEditable() )
-					comboBox.repaint();
+				if( comboBox != null )
+					HiDPIUtils.repaint( comboBox );
 			}
 		};
 	}
@@ -386,12 +387,12 @@ public class FlatComboBoxUI
 				switch( propertyName ) {
 					case PLACEHOLDER_TEXT:
 						if( editor != null )
-							editor.repaint();
+							HiDPIUtils.repaint( editor );
 						break;
 
 					case COMPONENT_ROUND_RECT:
 					case OUTLINE:
-						comboBox.repaint();
+						HiDPIUtils.repaint( comboBox );
 						break;
 
 					case MINIMUM_WIDTH:
@@ -402,7 +403,7 @@ public class FlatComboBoxUI
 					case STYLE_CLASS:
 						installStyle();
 						comboBox.revalidate();
-						comboBox.repaint();
+						HiDPIUtils.repaint( comboBox );
 						break;
 				}
 			}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatEditorPaneUI.java

@@ -171,7 +171,7 @@ public class FlatEditorPaneUI
 			case FlatClientProperties.STYLE_CLASS:
 				installStyle.run();
 				c.revalidate();
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 		}
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatFileChooserUI.java

@@ -24,6 +24,7 @@ import java.awt.Graphics2D;
 import java.awt.Image;
 import java.awt.Insets;
 import java.awt.LayoutManager;
+import java.awt.Rectangle;
 import java.awt.RenderingHints;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
@@ -32,6 +33,7 @@ import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.function.Function;
 import javax.swing.AbstractButton;
+import javax.swing.BorderFactory;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.ButtonGroup;
@@ -46,6 +48,7 @@ import javax.swing.JScrollPane;
 import javax.swing.JTable;
 import javax.swing.JToggleButton;
 import javax.swing.JToolBar;
+import javax.swing.Scrollable;
 import javax.swing.SwingConstants;
 import javax.swing.UIManager;
 import javax.swing.filechooser.FileSystemView;
@@ -164,6 +167,7 @@ public class FlatFileChooserUI
 {
 	private final FlatFileView fileView = new FlatFileView();
 	private FlatShortcutsPanel shortcutsPanel;
+	private JScrollPane shortcutsScrollPane;
 
 	public static ComponentUI createUI( JComponent c ) {
 		return new FlatFileChooserUI( (JFileChooser) c );
@@ -183,7 +187,10 @@ public class FlatFileChooserUI
 			FlatShortcutsPanel panel = createShortcutsPanel( fc );
 			if( panel.getComponentCount() > 0 ) {
 				shortcutsPanel = panel;
-				fc.add( shortcutsPanel, BorderLayout.LINE_START );
+				shortcutsScrollPane = new JScrollPane( shortcutsPanel,
+					JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER );
+				shortcutsScrollPane.setBorder( BorderFactory.createEmptyBorder() );
+				fc.add( shortcutsScrollPane, BorderLayout.LINE_START );
 				fc.addPropertyChangeListener( shortcutsPanel );
 			}
 		}
@@ -196,6 +203,7 @@ public class FlatFileChooserUI
 		if( shortcutsPanel != null ) {
 			fc.removePropertyChangeListener( shortcutsPanel );
 			shortcutsPanel = null;
+			shortcutsScrollPane = null;
 		}
 	}
 
@@ -324,7 +332,7 @@ public class FlatFileChooserUI
 	public Dimension getPreferredSize( JComponent c ) {
 		Dimension prefSize = super.getPreferredSize( c );
 		Dimension minSize = getMinimumSize( c );
-		int shortcutsPanelWidth = (shortcutsPanel != null) ? shortcutsPanel.getPreferredSize().width : 0;
+		int shortcutsPanelWidth = (shortcutsScrollPane != null) ? shortcutsScrollPane.getPreferredSize().width : 0;
 		return new Dimension(
 			Math.max( prefSize.width, minSize.width + shortcutsPanelWidth ),
 			Math.max( prefSize.height, minSize.height ) );
@@ -401,7 +409,7 @@ public class FlatFileChooserUI
 	/** @since 2.3 */
 	public static class FlatShortcutsPanel
 		extends JToolBar
-		implements PropertyChangeListener
+		implements PropertyChangeListener, Scrollable
 	{
 		private final JFileChooser fc;
 
@@ -420,6 +428,7 @@ public class FlatFileChooserUI
 			super( JToolBar.VERTICAL );
 			this.fc = fc;
 			setFloatable( false );
+			putClientProperty( FlatClientProperties.STYLE, "hoverButtonGroupBackground: null" );
 
 			buttonSize = UIScale.scale( getUIDimension( "FileChooser.shortcuts.buttonSize", 84, 64 ) );
 			iconSize = getUIDimension( "FileChooser.shortcuts.iconSize", 32, 32 );
@@ -461,7 +470,7 @@ public class FlatFileChooserUI
 					icon = new ShortcutIcon( icon, iconSize.width, iconSize.height );
 
 				// create button
-				JToggleButton button = createButton( name, icon );
+				JToggleButton button = createButton( name, icon, file.toString() );
 				File f = file;
 				button.addActionListener( e -> {
 					fc.setCurrentDirectory( f );
@@ -487,8 +496,10 @@ public class FlatFileChooserUI
 			return size;
 		}
 
-		protected JToggleButton createButton( String name, Icon icon ) {
+		/** @since 3.5 */
+		protected JToggleButton createButton( String name, Icon icon, String toolTip ) {
 			JToggleButton button = new JToggleButton( name, icon );
+			button.setToolTipText( toolTip );
 			button.setVerticalTextPosition( SwingConstants.BOTTOM );
 			button.setHorizontalTextPosition( SwingConstants.CENTER );
 			button.setAlignmentX( Component.CENTER_ALIGNMENT );
@@ -566,6 +577,8 @@ public class FlatFileChooserUI
 			buttonGroup.clearSelection();
 		}
 
+		//---- interface PropertyChangeListener ----
+
 		@Override
 		public void propertyChange( PropertyChangeEvent e ) {
 			switch( e.getPropertyName() ) {
@@ -574,6 +587,41 @@ public class FlatFileChooserUI
 					break;
 			}
 		}
+
+		//---- interface Scrollable ----
+
+		@Override
+		public Dimension getPreferredScrollableViewportSize() {
+			if( getComponentCount() > 0 ) {
+				Insets insets = getInsets();
+				int height = (getComponent( 0 ).getPreferredSize().height * 5) + insets.top + insets.bottom;
+				return new Dimension( getPreferredSize().width, height );
+			}
+			return getPreferredSize();
+		}
+
+		@Override
+		public int getScrollableUnitIncrement( Rectangle visibleRect, int orientation, int direction ) {
+			if( orientation == SwingConstants.VERTICAL && getComponentCount() > 0 )
+				return getComponent( 0 ).getPreferredSize().height;
+
+			return getScrollableBlockIncrement( visibleRect, orientation, direction ) / 10;
+		}
+
+		@Override
+		public int getScrollableBlockIncrement( Rectangle visibleRect, int orientation, int direction ) {
+			return (orientation == SwingConstants.VERTICAL) ? visibleRect.height : visibleRect.width;
+		}
+
+		@Override
+		public boolean getScrollableTracksViewportWidth() {
+			return true;
+		}
+
+		@Override
+		public boolean getScrollableTracksViewportHeight() {
+			return false;
+		}
 	}
 
 	//---- class ShortcutIcon -------------------------------------------------

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatHTML.java

@@ -0,0 +1,255 @@
+/*
+ * Copyright 2024 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.ui;
+
+import java.awt.Color;
+import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Set;
+import javax.swing.AbstractButton;
+import javax.swing.JComponent;
+import javax.swing.JLabel;
+import javax.swing.JToolTip;
+import javax.swing.plaf.basic.BasicHTML;
+import javax.swing.text.AttributeSet;
+import javax.swing.text.Document;
+import javax.swing.text.LabelView;
+import javax.swing.text.Style;
+import javax.swing.text.StyleConstants;
+import javax.swing.text.View;
+import javax.swing.text.html.CSS;
+import javax.swing.text.html.HTMLDocument;
+import javax.swing.text.html.StyleSheet;
+
+/**
+ * @author Karl Tauber
+ * @since 3.5
+ */
+public class FlatHTML
+{
+	private FlatHTML() {}
+
+	/**
+	 * Adds CSS rule BASE_SIZE to the style sheet of the HTML view,
+	 * which re-calculates font sizes based on current component font size.
+	 * This is necessary for "absolute-size" keywords (e.g. "x-large")
+	 * for "font-size" attributes in default style sheet (see javax/swing/text/html/default.css).
+	 * See also <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/font-size#values">CSS font-size</a>.
+	 * <p>
+	 * This method should be invoked after {@link BasicHTML#updateRenderer(JComponent, String)}.
+	 */
+	public static void updateRendererCSSFontBaseSize( JComponent c ) {
+		View view = (View) c.getClientProperty( BasicHTML.propertyKey );
+		if( view == null )
+			return;
+
+//		dumpViews( view, 0 );
+
+		Document doc = view.getDocument();
+		if( !(doc instanceof HTMLDocument) )
+			return;
+
+		// add BASE_SIZE rule if necessary
+		//  - if point size at index 7 is not 36, then probably HTML text contains BASE_SIZE rule
+		//  - if point size at index 4 is equal to given font size, then it is not necessary to add BASE_SIZE rule
+		StyleSheet styleSheet = ((HTMLDocument)doc).getStyleSheet();
+/*debug
+		for( int i = 1; i <= 7; i++ )
+			System.out.println( i+": "+ styleSheet.getPointSize( i ) );
+debug*/
+		int fontBaseSize = c.getFont().getSize();
+		if( styleSheet.getPointSize( 7 ) != 36f ||
+			styleSheet.getPointSize( 4 ) == fontBaseSize )
+		  return;
+
+		// check whether view uses "absolute-size" keywords (e.g. "x-large") for font-size
+		if( !usesAbsoluteSizeKeywordForFontSize( view ) )
+			return;
+
+		// get HTML text from component
+		String text;
+		if( c instanceof JLabel )
+			text = ((JLabel)c).getText();
+		else if( c instanceof AbstractButton )
+			text = ((AbstractButton)c).getText();
+		else if( c instanceof JToolTip )
+			text = ((JToolTip)c).getTipText();
+		else
+			return;
+		if( text == null )
+			return;
+
+		// BASE_SIZE rule is parsed in javax.swing.text.html.StyleSheet.addRule()
+		String style = "<style>BASE_SIZE " + c.getFont().getSize() + "</style>";
+		String openTag = "";
+		String closeTag = "";
+
+		String lowerText = text.toLowerCase( Locale.ENGLISH );
+		int headIndex;
+		int styleIndex;
+
+		int insertIndex;
+		if( (headIndex = lowerText.indexOf( "<head>" )) >= 0 ) {
+			// there is a <head> tag --> insert after <head> tag
+			insertIndex = headIndex + "<head>".length();
+		} else if( (styleIndex = lowerText.indexOf( "<style>" )) >= 0 ) {
+			// there is a <style> tag --> insert before <style> tag
+			insertIndex = styleIndex;
+		} else {
+			// no <head> or <style> tag --> insert <head> tag after <html> tag
+			insertIndex = "<html>".length();
+			openTag = "<head>";
+			closeTag = "</head>";
+		}
+
+		String newText = text.substring( 0, insertIndex )
+			+ openTag + style + closeTag
+			+ text.substring( insertIndex );
+
+		BasicHTML.updateRenderer( c, newText );
+	}
+
+	private static final Set<String> absoluteSizeKeywordsSet = new HashSet<>( Arrays.asList(
+		"xx-small", "x-small", "small", "medium", "large", "x-large", "xx-large" ) );
+
+	/**
+	 * Checks whether view uses "absolute-size" keywords (e.g. "x-large") for font-size
+	 * (see javax/swing/text/html/default.css).
+	 */
+	private static boolean usesAbsoluteSizeKeywordForFontSize( View view ) {
+		AttributeSet attributes = view.getAttributes();
+		if( attributes != null ) {
+			Object fontSize = attributes.getAttribute( CSS.Attribute.FONT_SIZE );
+			if( fontSize != null ) {
+				if( absoluteSizeKeywordsSet.contains( fontSize.toString() ) )
+					return true;
+			}
+		}
+
+		int viewCount = view.getViewCount();
+		for( int i = 0; i < viewCount; i++ ) {
+			if( usesAbsoluteSizeKeywordForFontSize( view.getView( i ) ) )
+				return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * Updates foreground in style sheet of the HTML view.
+	 * Adds "body { color: #&lt;foreground-hex&gt;; }"
+	 */
+	public static void updateRendererCSSForeground( View view, Color foreground ) {
+		Document doc = view.getDocument();
+		if( !(doc instanceof HTMLDocument) || foreground == null )
+			return;
+
+		// add foreground rule if necessary
+		//  - use tag 'body' because BasicHTML.createHTMLView() also uses this tag
+		//    to set font and color styles to component font/color
+		//    see: SwingUtilities2.displayPropertiesToCSS()
+		//  - this color is not used if component is disabled;
+		//    JTextComponent.getDisabledTextColor() is used for disabled text components;
+		//    UIManager.getColor("textInactiveText") is used for other disabled components
+		//    see: javax.swing.text.GlyphView.paint()
+		Style bodyStyle = ((HTMLDocument)doc).getStyle( "body" );
+		if( bodyStyle == null ) {
+			StyleSheet styleSheet = ((HTMLDocument)doc).getStyleSheet();
+			styleSheet.addRule( String.format( "body { color: #%06x; }", foreground.getRGB() & 0xffffff ) );
+			clearViewCaches( view );
+		} else if( !foreground.equals( bodyStyle.getAttribute( StyleConstants.Foreground ) ) ) {
+			bodyStyle.addAttribute( StyleConstants.Foreground, foreground );
+			clearViewCaches( view );
+		}
+	}
+
+	/**
+	 * Clears cached values in view so that CSS changes take effect.
+	 */
+	private static void clearViewCaches( View view ) {
+		if( view instanceof LabelView )
+			((LabelView)view).changedUpdate( null, null, null );
+
+		int viewCount = view.getViewCount();
+		for( int i = 0; i < viewCount; i++ )
+			clearViewCaches( view.getView( i ) );
+	}
+
+	public static PropertyChangeListener createPropertyChangeListener( PropertyChangeListener superListener ) {
+		return e -> {
+			if( superListener != null )
+				superListener.propertyChange( e );
+			propertyChange( e );
+		};
+	}
+
+	/**
+	 * Invokes {@link #updateRendererCSSFontBaseSize(JComponent)}
+	 * for {@link BasicHTML#propertyKey} property change events,
+	 * which are fired when {@link BasicHTML#updateRenderer(JComponent, String)}
+	 * updates the HTML view.
+	 */
+	public static void propertyChange( PropertyChangeEvent e ) {
+		if( BasicHTML.propertyKey.equals( e.getPropertyName() ) && e.getNewValue() instanceof View )
+			updateRendererCSSFontBaseSize( (JComponent) e.getSource() );
+	}
+
+/*debug
+	public static void dumpView( JComponent c ) {
+		View view = (View) c.getClientProperty( BasicHTML.propertyKey );
+		if( view != null )
+			dumpViews( view, 0 );
+	}
+
+	public static void dumpViews( View view, int indent ) {
+		for( int i = 0; i < indent; i++ )
+			System.out.print( "    " );
+
+		System.out.printf( "%s @%-8x   %3d,%2d",
+			view.getClass().isAnonymousClass() ? view.getClass().getName() : view.getClass().getSimpleName(),
+			System.identityHashCode( view ),
+			(int) view.getPreferredSpan( View.X_AXIS ),
+			(int) view.getPreferredSpan( View.Y_AXIS ) );
+
+		AttributeSet attrs = view.getAttributes();
+		if( attrs != null ) {
+			Object fontSize = attrs.getAttribute( CSS.Attribute.FONT_SIZE );
+			System.out.printf( "  %-8s", fontSize );
+		}
+
+		if( view instanceof javax.swing.text.GlyphView ) {
+			javax.swing.text.GlyphView gview = ((javax.swing.text.GlyphView)view);
+			java.awt.Font font = gview.getFont();
+			System.out.printf( "   %3d-%-3d  %s %2d (@%x)  #%06x  '%s'",
+				gview.getStartOffset(), gview.getEndOffset() - 1,
+				font.getName(), font.getSize(), System.identityHashCode( font ),
+				gview.getForeground().getRGB() & 0xffffff,
+				gview.getText( gview.getStartOffset(), gview.getEndOffset() ) );
+		}
+		System.out.println();
+
+		int viewCount = view.getViewCount();
+		for( int i = 0; i < viewCount; i++ ) {
+			View child = view.getView( i );
+			dumpViews( child, indent + 1 );
+		}
+	}
+debug*/
+}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatLabelUI.java

@@ -22,11 +22,7 @@ import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Rectangle;
 import java.beans.PropertyChangeEvent;
-import java.util.Arrays;
-import java.util.HashSet;
-import java.util.Locale;
 import java.util.Map;
-import java.util.Set;
 import javax.swing.Icon;
 import javax.swing.JComponent;
 import javax.swing.JLabel;
@@ -64,6 +60,9 @@ public class FlatLabelUI
 {
 	@Styleable protected Color disabledForeground;
 
+	// only used via styling (not in UI defaults)
+	/** @since 3.5 */ @Styleable protected int arc = -1;
+
 	private final boolean shared;
 	private boolean defaults_initialized = false;
 	private Map<String, Object> oldStyleValues;
@@ -110,16 +109,13 @@ public class FlatLabelUI
 		super.installComponents( c );
 
 		// update HTML renderer if necessary
-		updateHTMLRenderer( c, c.getText(), false );
+		FlatHTML.updateRendererCSSFontBaseSize( c );
 	}
 
 	@Override
 	public void propertyChange( PropertyChangeEvent e ) {
 		String name = e.getPropertyName();
-		if( name == "text" || name == "font" || name == "foreground" ) {
-			JLabel label = (JLabel) e.getSource();
-			updateHTMLRenderer( label, label.getText(), true );
-		} else if( name.equals( FlatClientProperties.STYLE ) || name.equals( FlatClientProperties.STYLE_CLASS ) ) {
+		if( name.equals( FlatClientProperties.STYLE ) || name.equals( FlatClientProperties.STYLE_CLASS ) ) {
 			JLabel label = (JLabel) e.getSource();
 			if( shared && FlatStylingSupport.hasStyleProperty( label ) ) {
 				// unshare component UI if necessary
@@ -128,9 +124,11 @@ public class FlatLabelUI
 			} else
 				installStyle( label );
 			label.revalidate();
-			label.repaint();
-		} else
+			HiDPIUtils.repaint( label );
+		}
+
 		super.propertyChange( e );
+		FlatHTML.propertyChange( e );
 	}
 
 	/** @since 2 */
@@ -165,83 +163,10 @@ public class FlatLabelUI
 		return FlatStylingSupport.getAnnotatedStyleableValue( this, key );
 	}
 
-	/**
-	 * Checks whether text contains HTML tags that use "absolute-size" keywords
-	 * (e.g. "x-large") for font-size in default style sheet
-	 * (see javax/swing/text/html/default.css).
-	 * If yes, adds a special CSS rule (BASE_SIZE) to the HTML text, which
-	 * re-calculates font sizes based on current component font size.
-	 */
-	static void updateHTMLRenderer( JComponent c, String text, boolean always ) {
-		if( BasicHTML.isHTMLString( text ) &&
-			c.getClientProperty( "html.disable" ) != Boolean.TRUE &&
-			needsFontBaseSize( text ) )
-		{
-			// BASE_SIZE rule is parsed in javax.swing.text.html.StyleSheet.addRule()
-			String style = "<style>BASE_SIZE " + c.getFont().getSize() + "</style>";
-
-			String lowerText = text.toLowerCase( Locale.ENGLISH );
-			int headIndex;
-			int styleIndex;
-
-			int insertIndex;
-			if( (headIndex = lowerText.indexOf( "<head>" )) >= 0 ) {
-				// there is a <head> tag --> insert after <head> tag
-				insertIndex = headIndex + "<head>".length();
-			} else if( (styleIndex = lowerText.indexOf( "<style>" )) >= 0 ) {
-				// there is a <style> tag --> insert before <style> tag
-				insertIndex = styleIndex;
-			} else {
-				// no <head> or <style> tag --> insert <head> tag after <html> tag
-				style = "<head>" + style + "</head>";
-				insertIndex = "<html>".length();
-			}
-
-			text = text.substring( 0, insertIndex )
-				+ style
-				+ text.substring( insertIndex );
-		} else if( !always )
-			return; // not necessary to invoke BasicHTML.updateRenderer()
-
-		BasicHTML.updateRenderer( c, text );
-	}
-
-	private static Set<String> tagsUseFontSizeSet;
-
-	private static boolean needsFontBaseSize( String text ) {
-		if( tagsUseFontSizeSet == null ) {
-			// tags that use font-size in javax/swing/text/html/default.css
-			tagsUseFontSizeSet = new HashSet<>( Arrays.asList(
-				"h1", "h2", "h3", "h4", "h5", "h6", "code", "kbd", "big", "small", "samp" ) );
-		}
-
-		// search for tags in HTML text
-		int textLength = text.length();
-		for( int i = 6; i < textLength - 1; i++ ) {
-			if( text.charAt( i ) == '<' ) {
-				switch( text.charAt( i + 1 ) ) {
-					// first letters of tags in tagsUseFontSizeSet
-					case 'b': case 'B':
-					case 'c': case 'C':
-					case 'h': case 'H':
-					case 'k': case 'K':
-					case 's': case 'S':
-						int tagBegin = i + 1;
-						for( i += 2; i < textLength; i++ ) {
-							if( !Character.isLetterOrDigit( text.charAt( i ) ) ) {
-								String tag = text.substring( tagBegin, i ).toLowerCase( Locale.ENGLISH );
-								if( tagsUseFontSizeSet.contains( tag ) )
-									return true;
-
-								break;
-							}
-						}
-						break;
-				}
-			}
-		}
-
-		return false;
+	@Override
+	public void update( Graphics g, JComponent c ) {
+		FlatPanelUI.fillRoundedBackground( g, c, arc );
+		paint( g, c );
 	}
 
 	static Graphics createGraphicsHTMLTextYCorrection( Graphics g, JComponent c ) {

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatLineBorder.java

@@ -23,13 +23,20 @@ import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
 import javax.swing.JComponent;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.plaf.ComponentUI;
 
 /**
  * Line border for various components.
- *
+ * <p>
  * Paints a scaled (usually 1px thick) line around the component.
  * The line thickness is not added to the border insets.
  * The insets should be at least have line thickness (usually 1,1,1,1).
+ * <p>
+ * For {@link javax.swing.JPanel} and {@link javax.swing.JLabel}, this border
+ * can be used paint rounded background (if line color is {@code null}) or
+ * paint rounded line border with rounded background.
  *
  * @author Karl Tauber
  */
@@ -41,7 +48,7 @@ public class FlatLineBorder
 	/** @since 2 */ private final int arc;
 
 	public FlatLineBorder( Insets insets, Color lineColor ) {
-		this( insets, lineColor, 1f, 0 );
+		this( insets, lineColor, 1f, -1 );
 	}
 
 	/** @since 2 */
@@ -52,15 +59,28 @@ public class FlatLineBorder
 		this.arc = arc;
 	}
 
+	/** @since 3.5 */
+	public FlatLineBorder( Insets insets, int arc ) {
+		this( insets, null, 0, arc );
+	}
+
 	public Color getLineColor() {
 		return lineColor;
 	}
 
+	/**
+	 * Returns the (unscaled) line thickness used to paint the border.
+	 * The line thickness does not affect the border insets.
+	 */
 	public float getLineThickness() {
 		return lineThickness;
 	}
 
-	/** @since 2 */
+	/**
+	 * Returns the (unscaled) arc diameter of the border corners.
+	 *
+	 * @since 2
+	 */
 	public int getArc() {
 		return arc;
 	}
@@ -70,11 +90,31 @@ public class FlatLineBorder
 		if( c instanceof JComponent && ((JComponent)c).getClientProperty( FlatPopupFactory.KEY_POPUP_USES_NATIVE_BORDER ) != null )
 			return;
 
+		Color lineColor = getLineColor();
+		float lineThickness = getLineThickness();
+		if( lineColor == null || lineThickness <= 0 )
+			return;
+
+		int arc = getArc();
+		if( arc < 0 ) {
+			// get arc from label or panel
+			ComponentUI ui = (c instanceof JLabel)
+				? ((JLabel)c).getUI()
+				: (c instanceof JPanel ? ((JPanel)c).getUI() : null);
+			if( ui instanceof FlatLabelUI )
+				arc = ((FlatLabelUI)ui).arc;
+			else if( ui instanceof FlatPanelUI )
+				arc = ((FlatPanelUI)ui).arc;
+
+			if( arc < 0 )
+				arc = 0;
+		}
+
 		Graphics2D g2 = (Graphics2D) g.create();
 		try {
 			FlatUIUtils.setRenderingHints( g2 );
 			FlatUIUtils.paintOutlinedComponent( g2, x, y, width, height,
-				0, 0, 0, scale( getLineThickness() ), scale( getArc() ), null, getLineColor(), null );
+				0, 0, 0, scale( lineThickness ), scale( arc ), null, lineColor, null );
 		} finally {
 			g2.dispose();
 		}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatListUI.java

@@ -43,6 +43,7 @@ import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.util.Graphics2DProxy;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -182,7 +183,7 @@ public class FlatListUI
 				case FlatClientProperties.STYLE_CLASS:
 					installStyle();
 					list.revalidate();
-					list.repaint();
+					HiDPIUtils.repaint( list );
 					break;
 			}
 		};
@@ -205,7 +206,7 @@ public class FlatListUI
 				Rectangle r = getCellBounds( list, firstIndex, lastIndex );
 				if( r != null ) {
 					int arc = (int) Math.ceil( UIScale.scale( selectionArc / 2f ) );
-					list.repaint( r.x - arc, r.y - arc, r.width + (arc * 2), r.height + (arc * 2) );
+					HiDPIUtils.repaint( list, r.x - arc, r.y - arc, r.width + (arc * 2), r.height + (arc * 2) );
 				}
 			}
 		};
@@ -324,8 +325,7 @@ public class FlatListUI
 			(rendererComponent instanceof DefaultListCellRenderer ||
 			 rendererComponent instanceof BasicComboBoxRenderer) &&
 			(selectionArc > 0 ||
-			 (selectionInsets != null &&
-			  (selectionInsets.top != 0 || selectionInsets.left != 0 || selectionInsets.bottom != 0 || selectionInsets.right != 0))) )
+			 (selectionInsets != null && !FlatUIUtils.isInsetsEmpty( selectionInsets ))) )
 		{
 			// Because selection painting is done in the cell renderer, it would be
 			// necessary to require a FlatLaf specific renderer to implement rounded selection.
@@ -374,7 +374,15 @@ public class FlatListUI
 		rendererPane.paintComponent( g, rendererComponent, list, cx, rowBounds.y, cw, rowBounds.height, true );
 	}
 
-	/** @since 3 */
+	/**
+	 * Paints (rounded) cell selection.
+	 * Supports {@link #selectionArc} and {@link #selectionInsets}.
+	 * <p>
+	 * <b>Note:</b> This method is only invoked if either selection arc
+	 *              is greater than zero or if selection insets are not empty.
+	 *
+	 * @since 3
+	 */
 	protected void paintCellSelection( Graphics g, int row, int x, int y, int width, int height ) {
 		float arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight;
 		arcTopLeft = arcTopRight = arcBottomLeft = arcBottomRight = UIScale.scale( selectionArc / 2f );
@@ -440,7 +448,8 @@ public class FlatListUI
 	 * Paints a cell selection at the given coordinates.
 	 * The selection color must be set on the graphics context.
 	 * <p>
-	 * This method is intended for use in custom cell renderers.
+	 * This method is intended for use in custom cell renderers
+	 * to support {@link #selectionArc} and {@link #selectionInsets}.
 	 *
 	 * @since 3
 	 */

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatMenuItemRenderer.java

@@ -25,7 +25,9 @@ import java.awt.Font;
 import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
+import java.awt.GridLayout;
 import java.awt.Insets;
+import java.awt.LayoutManager;
 import java.awt.Paint;
 import java.awt.Rectangle;
 import java.awt.event.InputEvent;
@@ -35,6 +37,7 @@ import java.util.Map;
 import javax.swing.Icon;
 import javax.swing.JComponent;
 import javax.swing.JMenu;
+import javax.swing.JMenuBar;
 import javax.swing.JMenuItem;
 import javax.swing.KeyStroke;
 import javax.swing.SwingUtilities;
@@ -222,7 +225,7 @@ public class FlatMenuItemRenderer
 		}
 
 		// arrow size
-		if( !isTopLevelMenu && arrowIcon != null ) {
+		if( arrowIcon != null && (!isTopLevelMenu || isInVerticalMenuBar( menuItem )) ) {
 			// gap between text and arrow
 			if( accelText == null )
 				width += scale( textNoAcceleratorGap );
@@ -254,7 +257,8 @@ public class FlatMenuItemRenderer
 		boolean isTopLevelMenu = isTopLevelMenu( menuItem );
 
 		// layout arrow
-		if( !isTopLevelMenu && arrowIcon != null ) {
+		boolean showArrowIcon = (arrowIcon != null && (!isTopLevelMenu || isInVerticalMenuBar( menuItem )));
+		if( showArrowIcon ) {
 			arrowRect.width = arrowIcon.getIconWidth();
 			arrowRect.height = arrowIcon.getIconHeight();
 		} else
@@ -288,7 +292,7 @@ public class FlatMenuItemRenderer
 		int accelArrowWidth = accelRect.width + arrowRect.width;
 		if( accelText != null )
 			accelArrowWidth += scale( !isTopLevelMenu ? textAcceleratorGap : menuItem.getIconTextGap() );
-		if( !isTopLevelMenu && arrowIcon != null ) {
+		if( showArrowIcon ) {
 			if( accelText == null )
 				accelArrowWidth += scale( textNoAcceleratorGap );
 			accelArrowWidth += scale( acceleratorArrowGap );
@@ -355,7 +359,7 @@ debug*/
 		paintIcon( g, iconRect, getIconForPainting(), underlineSelection ? underlineSelectionCheckBackground : checkBackground, selectionBackground );
 		paintText( g, textRect, menuItem.getText(), selectionForeground, disabledForeground );
 		paintAccelerator( g, accelRect, getAcceleratorText(), acceleratorForeground, acceleratorSelectionForeground, disabledForeground );
-		if( !isTopLevelMenu( menuItem ) )
+		if( arrowIcon != null && (!isTopLevelMenu( menuItem ) || isInVerticalMenuBar( menuItem )) )
 			paintArrowIcon( g, arrowRect, arrowIcon );
 	}
 
@@ -520,6 +524,15 @@ debug*/
 		return menuItem instanceof JMenu && ((JMenu)menuItem).isTopLevelMenu();
 	}
 
+	/** @since 3.5 */
+	public static boolean isInVerticalMenuBar( JMenuItem menuItem ) {
+		if( !(menuItem instanceof JMenu) || !(menuItem.getParent() instanceof JMenuBar) )
+			return false;
+
+		LayoutManager layout = menuItem.getParent().getLayout();
+		return layout instanceof GridLayout && ((GridLayout)layout).getRows() != 1;
+	}
+
 	protected boolean isUnderlineSelection() {
 		return "underline".equals( UIManager.getString( "MenuItem.selectionType" ) );
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatMenuItemUI.java

@@ -103,13 +103,23 @@ public class FlatMenuItemUI
 		oldStyleValues = null;
 	}
 
+	@Override
+	protected void installComponents( JMenuItem menuItem ) {
+		super.installComponents( menuItem );
+
+		// update HTML renderer if necessary
+		FlatHTML.updateRendererCSSFontBaseSize( menuItem );
+	}
+
 	protected FlatMenuItemRenderer createRenderer() {
 		return new FlatMenuItemRenderer( menuItem, checkIcon, arrowIcon, acceleratorFont, acceleratorDelimiter );
 	}
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+		return FlatHTML.createPropertyChangeListener(
+			FlatStylingSupport.createPropertyChangeListener( c, this::installStyle,
+				super.createPropertyChangeListener( c ) ) );
 	}
 
 	/** @since 2 */

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatMenuUI.java

@@ -47,6 +47,7 @@ import javax.swing.plaf.basic.BasicMenuUI;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableField;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableLookupProvider;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 
 /**
@@ -136,6 +137,14 @@ public class FlatMenuUI
 		oldStyleValues = null;
 	}
 
+	@Override
+	protected void installComponents( JMenuItem menuItem ) {
+		super.installComponents( menuItem );
+
+		// update HTML renderer if necessary
+		FlatHTML.updateRendererCSSFontBaseSize( menuItem );
+	}
+
 	protected FlatMenuItemRenderer createRenderer() {
 		return new FlatMenuRenderer( menuItem, checkIcon, arrowIcon, acceleratorFont, acceleratorDelimiter );
 	}
@@ -159,7 +168,7 @@ public class FlatMenuUI
 				JMenu menu = (JMenu) e.getSource();
 				if( menu.isTopLevelMenu() && menu.isRolloverEnabled() ) {
 					menu.getModel().setRollover( rollover );
-					menu.repaint();
+					HiDPIUtils.repaint( menu );
 				}
 			}
 		};
@@ -167,7 +176,9 @@ public class FlatMenuUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+		return FlatHTML.createPropertyChangeListener(
+			FlatStylingSupport.createPropertyChangeListener( c, this::installStyle,
+				super.createPropertyChangeListener( c ) ) );
 	}
 
 	/** @since 2 */

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeLibrary.java

@@ -37,16 +37,18 @@ class FlatNativeLibrary
 	private static boolean initialized;
 	private static NativeLibrary nativeLibrary;
 
+	private native static int getApiVersion();
+
 	/**
 	 * Loads native library (if available) and returns whether loaded successfully.
 	 * Returns {@code false} if no native library is available.
 	 */
-	static synchronized boolean isLoaded() {
-		initialize();
+	static synchronized boolean isLoaded( int apiVersion ) {
+		initialize( apiVersion );
 		return (nativeLibrary != null) ? nativeLibrary.isLoaded() : false;
 	}
 
-	private static void initialize() {
+	private static void initialize( int apiVersion ) {
 		if( initialized )
 			return;
 		initialized = true;
@@ -104,7 +106,26 @@ class FlatNativeLibrary
 			return; // no native library available for current OS or CPU architecture
 
 		// load native library
-		nativeLibrary = createNativeLibrary( classifier, ext );
+		NativeLibrary nativeLibrary = createNativeLibrary( classifier, ext );
+		if( !nativeLibrary.isLoaded() )
+			return;
+
+		// check API version (and check whether library works)
+		try {
+			int actualApiVersion = getApiVersion();
+			if( actualApiVersion != apiVersion ) {
+				LoggingFacade.INSTANCE.logSevere( "FlatLaf: Wrong API version in native library (expected "
+					+ apiVersion + ", actual " + actualApiVersion + "). Ignoring native library.", null );
+				return;
+			}
+		} catch( Throwable ex ) {
+			// could be a UnsatisfiedLinkError in case that loading native library
+			// from temp directory was blocked by some OS security mechanism
+			LoggingFacade.INSTANCE.logSevere( "FlatLaf: Failed to get API version of native library. Ignoring native library.", ex );
+			return;
+		}
+
+		FlatNativeLibrary.nativeLibrary = nativeLibrary;
 	}
 
 	private static NativeLibrary createNativeLibrary( String classifier, String ext ) {
@@ -118,9 +139,9 @@ class FlatNativeLibrary
 				if( library.isLoaded() )
 					return library;
 
-				LoggingFacade.INSTANCE.logSevere( "Did not find library '" + System.mapLibraryName( libraryName )
-					+ "' in java.library.path '" + System.getProperty( "java.library.path" )
-					+ "', using extracted library instead", null );
+				LoggingFacade.INSTANCE.logSevere( "FlatLaf: Native library '" + System.mapLibraryName( libraryName )
+					+ "' not found in java.library.path '" + System.getProperty( "java.library.path" )
+					+ "'. Using extracted native library instead.", null );
 			} else {
 				// try standard library naming scheme
 				// (same as in flatlaf.jar in package 'com/formdev/flatlaf/natives')
@@ -139,11 +160,11 @@ class FlatNativeLibrary
 						return new NativeLibrary( libraryFile2, true );
 				}
 
-				LoggingFacade.INSTANCE.logSevere( "Did not find library '"
+				LoggingFacade.INSTANCE.logSevere( "FlatLaf: Native library '"
 					+ libraryFile.getName()
 					+ (libraryName2 != null ? ("' or '" + libraryName2) : "")
-					+ "' in '" + libraryFile.getParentFile().getAbsolutePath()
-					+ "', using extracted library instead", null );
+					+ "' not found in '" + libraryFile.getParentFile().getAbsolutePath()
+					+ "'. Using extracted native library instead.", null );
 			}
 		}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeLinuxLibrary.java

@@ -35,6 +35,8 @@ import com.formdev.flatlaf.util.SystemInfo;
  */
 class FlatNativeLinuxLibrary
 {
+	private static int API_VERSION_LINUX = 3001;
+
 	/**
 	 * Checks whether native library is loaded/available.
 	 * <p>
@@ -42,7 +44,7 @@ class FlatNativeLinuxLibrary
 	 *              method of this class. Otherwise, the native library may not be loaded.
 	 */
 	static boolean isLoaded() {
-		return SystemInfo.isLinux && FlatNativeLibrary.isLoaded();
+		return SystemInfo.isLinux && FlatNativeLibrary.isLoaded( API_VERSION_LINUX );
 	}
 
 	// direction for _NET_WM_MOVERESIZE message

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeMacLibrary.java

@@ -44,6 +44,8 @@ import com.formdev.flatlaf.util.SystemInfo;
  */
 public class FlatNativeMacLibrary
 {
+	private static int API_VERSION_MACOS = 2001;
+
 	/**
 	 * Checks whether native library is loaded/available.
 	 * <p>
@@ -51,7 +53,7 @@ public class FlatNativeMacLibrary
 	 *              method of this class. Otherwise, the native library may not be loaded.
 	 */
 	public static boolean isLoaded() {
-		return SystemInfo.isMacOS && FlatNativeLibrary.isLoaded();
+		return SystemInfo.isMacOS && FlatNativeLibrary.isLoaded( API_VERSION_MACOS );
 	}
 
 	public native static boolean setWindowRoundedBorder( Window window, float radius, float borderWidth, int borderColor );

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatNativeWindowsLibrary.java

@@ -30,6 +30,8 @@ import com.formdev.flatlaf.util.SystemInfo;
  */
 public class FlatNativeWindowsLibrary
 {
+	private static int API_VERSION_WINDOWS = 1001;
+
 	private static long osBuildNumber = Long.MIN_VALUE;
 
 	/**
@@ -39,7 +41,7 @@ public class FlatNativeWindowsLibrary
 	 *              method of this class. Otherwise, the native library may not be loaded.
 	 */
 	public static boolean isLoaded() {
-		return SystemInfo.isWindows && FlatNativeLibrary.isLoaded();
+		return SystemInfo.isWindows && FlatNativeLibrary.isLoaded( API_VERSION_WINDOWS );
 	}
 
 	/**

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPanelUI.java

@@ -25,11 +25,13 @@ import java.util.Map;
 import javax.swing.JComponent;
 import javax.swing.JPanel;
 import javax.swing.LookAndFeel;
+import javax.swing.border.Border;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicPanelUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -110,7 +112,7 @@ public class FlatPanelUI
 				} else
 					installStyle( c );
 				c.revalidate();
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER:
@@ -160,32 +162,38 @@ public class FlatPanelUI
 
 	@Override
 	public void update( Graphics g, JComponent c ) {
-		// fill background
-		if( c.isOpaque() ) {
-			int width = c.getWidth();
-			int height = c.getHeight();
-			int arc = (this.arc >= 0)
-				? this.arc
-				: ((c.getBorder() instanceof FlatLineBorder)
-					? ((FlatLineBorder)c.getBorder()).getArc()
-					: 0);
-
-			// fill background with parent color to avoid garbage in rounded corners
-			if( arc > 0 )
-				FlatUIUtils.paintParentBackground( g, c );
-
-			g.setColor( c.getBackground() );
-			if( arc > 0 ) {
-				// fill rounded rectangle if having rounded corners
-				Object[] oldRenderingHints = FlatUIUtils.setRenderingHints( g );
-				FlatUIUtils.paintComponentBackground( (Graphics2D) g, 0, 0, width, height,
-					0, UIScale.scale( arc ) );
-				FlatUIUtils.resetRenderingHints( g, oldRenderingHints );
-			} else
-				g.fillRect( 0, 0, width, height );
+		fillRoundedBackground( g, c, arc );
+		paint( g, c );
 	}
 
-		paint( g, c );
+	/** @since 3.5 */
+	public static void fillRoundedBackground( Graphics g, JComponent c, int arc ) {
+		if( arc < 0 ) {
+			Border border = c.getBorder();
+			arc = ((border instanceof FlatLineBorder)
+				? ((FlatLineBorder)border).getArc()
+				: 0);
+		}
+
+		// fill background
+		if( c.isOpaque() ) {
+			if( arc > 0 ) {
+				// fill background with parent color to avoid garbage in rounded corners
+				FlatUIUtils.paintParentBackground( g, c );
+			} else {
+				g.setColor( c.getBackground() );
+				g.fillRect( 0, 0, c.getWidth(), c.getHeight() );
+			}
+		}
+
+		// fill rounded rectangle if having rounded corners
+		if( arc > 0 ) {
+			g.setColor( c.getBackground() );
+			Object[] oldRenderingHints = FlatUIUtils.setRenderingHints( g );
+			FlatUIUtils.paintComponentBackground( (Graphics2D) g, 0, 0, c.getWidth(), c.getHeight(),
+				0, UIScale.scale( arc ) );
+			FlatUIUtils.resetRenderingHints( g, oldRenderingHints );
+		}
 	}
 
 	@Override

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPasswordFieldUI.java

@@ -43,6 +43,7 @@ import javax.swing.text.View;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.icons.FlatCapsLockIcon;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.UIScale;
 
 /**
@@ -163,7 +164,7 @@ public class FlatPasswordFieldUI
 			}
 			private void repaint( KeyEvent e ) {
 				if( e.getKeyCode() == KeyEvent.VK_CAPS_LOCK ) {
-					e.getComponent().repaint();
+					HiDPIUtils.repaint( e.getComponent() );
 					scrollCaretToVisible();
 				}
 			}
@@ -326,7 +327,7 @@ public class FlatPasswordFieldUI
 		if( visible != revealButton.isVisible() ) {
 			revealButton.setVisible( visible );
 			c.revalidate();
-			c.repaint();
+			HiDPIUtils.repaint( c );
 
 			if( !visible ) {
 				revealButton.setSelected( false );

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java

@@ -17,6 +17,7 @@
 package com.formdev.flatlaf.ui;
 
 import java.awt.AWTEvent;
+import java.awt.BorderLayout;
 import java.awt.Color;
 import java.awt.Component;
 import java.awt.Container;
@@ -35,12 +36,16 @@ import java.awt.Toolkit;
 import java.awt.Window;
 import java.awt.event.ComponentEvent;
 import java.awt.event.ComponentListener;
+import java.awt.event.HierarchyEvent;
+import java.awt.event.HierarchyListener;
 import java.awt.event.MouseEvent;
 import java.awt.event.WindowFocusListener;
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.concurrent.atomic.AtomicReference;
 import javax.swing.JComponent;
 import javax.swing.JLayeredPane;
 import javax.swing.JPanel;
@@ -58,6 +63,7 @@ import javax.swing.border.EmptyBorder;
 import javax.swing.border.LineBorder;
 import javax.swing.plaf.basic.BasicComboPopup;
 import com.formdev.flatlaf.FlatClientProperties;
+import com.formdev.flatlaf.FlatSystemProperties;
 import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -76,6 +82,8 @@ public class FlatPopupFactory
 	private MethodHandle java8getPopupMethod;
 	private MethodHandle java9getPopupMethod;
 
+	private final ArrayList<NonFlashingPopup> stillShownHeavyWeightPopups = new ArrayList<>();
+
 	@Override
 	public Popup getPopup( Component owner, Component contents, int x, int y )
 		throws IllegalArgumentException
@@ -88,15 +96,28 @@ public class FlatPopupFactory
 
 		fixLinuxWaylandJava21focusIssue( owner );
 
+		// reuse a heavy weight popup window, which is still shown on screen,
+		// to avoid flicker when popup (e.g. tooltip) is moving while mouse is moved
+		for( NonFlashingPopup popup : stillShownHeavyWeightPopups ) {
+			if( popup.delegate != null &&
+				popup.owner == owner &&
+				(popup.contents == contents ||
+				 (popup.contents instanceof JToolTip && contents instanceof JToolTip)) )
+			{
+				stillShownHeavyWeightPopups.remove( popup );
+				return reuseStillShownHeavyWeightPopups( popup, contents, x, y );
+			}
+		}
+
 		boolean forceHeavyWeight = isOptionEnabled( owner, contents, FlatClientProperties.POPUP_FORCE_HEAVY_WEIGHT, "Popup.forceHeavyWeight" );
 
 		if( !isOptionEnabled( owner, contents, FlatClientProperties.POPUP_DROP_SHADOW_PAINTED, "Popup.dropShadowPainted" ) || SystemInfo.isProjector || SystemInfo.isWebswing )
-			return new NonFlashingPopup( getPopupForScreenOfOwner( owner, contents, x, y, forceHeavyWeight ), contents );
+			return new NonFlashingPopup( getPopupForScreenOfOwner( owner, contents, x, y, forceHeavyWeight ), owner, contents );
 
 		// macOS and Linux adds drop shadow to heavy weight popups
 		if( SystemInfo.isMacOS || SystemInfo.isLinux ) {
-			NonFlashingPopup popup = new NonFlashingPopup( getPopupForScreenOfOwner( owner, contents, x, y, true ), contents );
-			if( popup.popupWindow != null && SystemInfo.isMacOS && FlatNativeMacLibrary.isLoaded() )
+			NonFlashingPopup popup = new NonFlashingPopup( getPopupForScreenOfOwner( owner, contents, x, y, true ), owner, contents );
+			if( popup.popupWindow != null && isMacOSBorderSupported() )
 				setupRoundedBorder( popup.popupWindow, owner, contents );
 			return popup;
 		}
@@ -105,7 +126,7 @@ public class FlatPopupFactory
 		if( isWindows11BorderSupported() &&
 			getBorderCornerRadius( owner, contents ) > 0 )
 		{
-			NonFlashingPopup popup = new NonFlashingPopup( getPopupForScreenOfOwner( owner, contents, x, y, true ), contents );
+			NonFlashingPopup popup = new NonFlashingPopup( getPopupForScreenOfOwner( owner, contents, x, y, true ), owner, contents );
 			if( popup.popupWindow != null )
 				setupRoundedBorder( popup.popupWindow, owner, contents );
 			return popup;
@@ -116,7 +137,10 @@ public class FlatPopupFactory
 			forceHeavyWeight = true;
 
 		// create drop shadow popup
-		return new DropShadowPopup( getPopupForScreenOfOwner( owner, contents, x, y, forceHeavyWeight ), owner, contents );
+		Popup popupForScreenOfOwner = getPopupForScreenOfOwner( owner, contents, x, y, forceHeavyWeight );
+		return owner.getGraphicsConfiguration().isTranslucencyCapable()
+			? new DropShadowPopup( popupForScreenOfOwner, owner, contents )
+			: new NonFlashingPopup( popupForScreenOfOwner, owner, contents );
 	}
 
 	/**
@@ -227,6 +251,24 @@ public class FlatPopupFactory
 		return UIManager.get( uiKey );
 	}
 
+	/**
+	 * Reuse a heavy weight popup window, which is still shown on screen,
+	 * by updating window location and contents.
+	 * This avoid flicker when popup (e.g. a tooltip) is moving while mouse is moved.
+	 * E.g. overridden JComponent.getToolTipLocation(MouseEvent).
+	 * See ToolTipManager.checkForTipChange(MouseEvent).
+	 */
+	private static NonFlashingPopup reuseStillShownHeavyWeightPopups(
+		NonFlashingPopup reusePopup, Component contents, int ownerX, int ownerY )
+	{
+		// clone popup because PopupFactory.getPopup() should not return old instance
+		NonFlashingPopup popup = reusePopup.cloneForReuse();
+
+		// update popup location, size and contents
+		popup.reset( contents, ownerX, ownerY );
+		return popup;
+	}
+
 	//---- tooltips -----------------------------------------------------------
 
 	/**
@@ -316,19 +358,29 @@ public class FlatPopupFactory
 	//---- native rounded border ----------------------------------------------
 
 	private static boolean isWindows11BorderSupported() {
-		return SystemInfo.isWindows_11_orLater && FlatNativeWindowsLibrary.isLoaded();
+		return SystemInfo.isWindows_11_orLater &&
+			FlatSystemProperties.getBoolean( FlatSystemProperties.USE_ROUNDED_POPUP_BORDER, true ) &&
+			FlatNativeWindowsLibrary.isLoaded();
+	}
+
+	private static boolean isMacOSBorderSupported() {
+		// do not use rounded border on macOS 14.4+ because it may freeze the application
+		// and crash the macOS WindowServer process (reports vary from Finder restarts to OS restarts)
+		// https://github.com/apache/netbeans/issues/7560#issuecomment-2226439215
+		// https://github.com/apache/netbeans/issues/6647#issuecomment-2070124442
+		boolean isMacOS_14_4_orLater = (SystemInfo.osVersion >= SystemInfo.toVersion( 14, 4, 0, 0 ));
+
+		return SystemInfo.isMacOS &&
+			FlatSystemProperties.getBoolean( FlatSystemProperties.USE_ROUNDED_POPUP_BORDER, !isMacOS_14_4_orLater ) &&
+			FlatNativeMacLibrary.isLoaded();
 	}
 
 	private static void setupRoundedBorder( Window popupWindow, Component owner, Component contents ) {
-		// make sure that the native window is created
-		if( !popupWindow.isDisplayable() )
-			popupWindow.addNotify();
-
 		int borderCornerRadius = getBorderCornerRadius( owner, contents );
 		float borderWidth = getRoundedBorderWidth( owner, contents );
 
 		// get Swing border color
-		Color borderColor = null; // use system default color
+		Color borderColor;
 		if( contents instanceof JComponent ) {
 			Border border = ((JComponent)contents).getBorder();
 			border = FlatUIUtils.unwrapNonUIResourceBorder( border );
@@ -340,11 +392,33 @@ public class FlatPopupFactory
 				borderColor = ((LineBorder)border).getLineColor();
 			else if( border instanceof EmptyBorder )
 				borderColor = FlatNativeWindowsLibrary.COLOR_NONE; // do not paint border
+			else
+				borderColor = null; // use system default color
 
 			// avoid that FlatLineBorder paints the Swing border
 			((JComponent)contents).putClientProperty( KEY_POPUP_USES_NATIVE_BORDER, true );
+		} else
+			borderColor = null; // use system default color
+
+		if( popupWindow.isDisplayable() ) {
+			// native window already created
+			setupRoundedBorderImpl( popupWindow, borderCornerRadius, borderWidth, borderColor );
+		} else {
+			// native window not yet created --> add listener to set native border after window creation
+			AtomicReference<HierarchyListener> l = new AtomicReference<>();
+			l.set( e -> {
+				if( e.getID() == HierarchyEvent.HIERARCHY_CHANGED &&
+					(e.getChangeFlags() & HierarchyEvent.DISPLAYABILITY_CHANGED) != 0 )
+				{
+					setupRoundedBorderImpl( popupWindow, borderCornerRadius, borderWidth, borderColor );
+					popupWindow.removeHierarchyListener( l.get() );
+				}
+			} );
+			popupWindow.addHierarchyListener( l.get() );
+		}
 	}
 
+	private static void setupRoundedBorderImpl( Window popupWindow, int borderCornerRadius, float borderWidth, Color borderColor ) {
 		if( SystemInfo.isWindows ) {
 			// get native window handle
 			long hwnd = FlatNativeWindowsLibrary.getHWND( popupWindow );
@@ -490,18 +564,31 @@ public class FlatPopupFactory
 
 	//---- class NonFlashingPopup ---------------------------------------------
 
-	private static class NonFlashingPopup
+	/**
+	 * Fixes popup background flashing effect when using dark theme on light platform theme,
+	 * where the light popup background is shown for a fraction of a second before
+	 * the dark popup content is shown.
+	 * This is fixed by setting popup background to content background.
+	 * <p>
+	 * Defers hiding of heavy weight popup window for an event cycle,
+	 * which allows reusing popup window to avoid flicker when "moving" popup.
+	 */
+	private class NonFlashingPopup
 		extends Popup
 	{
 		private Popup delegate;
+		Component owner;
 		private Component contents;
 
 		// heavy weight
-		protected Window popupWindow;
+		Window popupWindow;
 		private Color oldPopupWindowBackground;
 
-		NonFlashingPopup( Popup delegate, Component contents ) {
+		private boolean disposed;
+
+		NonFlashingPopup( Popup delegate, Component owner, Component contents ) {
 			this.delegate = delegate;
+			this.owner = owner;
 			this.contents = contents;
 
 			popupWindow = SwingUtilities.windowForComponent( contents );
@@ -515,8 +602,27 @@ public class FlatPopupFactory
 			}
 		}
 
+		private NonFlashingPopup( NonFlashingPopup reusePopup ) {
+			delegate = reusePopup.delegate;
+			owner = reusePopup.owner;
+			contents = reusePopup.contents;
+			popupWindow = reusePopup.popupWindow;
+			oldPopupWindowBackground = reusePopup.oldPopupWindowBackground;
+		}
+
+		NonFlashingPopup cloneForReuse() {
+			return new NonFlashingPopup( this );
+		}
+
 		@Override
-		public void show() {
+		public final void show() {
+			if( disposed )
+				return;
+
+			showImpl();
+		}
+
+		void showImpl() {
 			if( delegate != null ) {
 				showPopupAndFixLocation( delegate, popupWindow );
 
@@ -540,13 +646,36 @@ public class FlatPopupFactory
 		}
 
 		@Override
-		public void hide() {
+		public final void hide() {
+			if( disposed )
+				return;
+			disposed = true;
+
+			// immediately hide non-heavy weight popups or combobox popups
+			if( !(popupWindow instanceof JWindow) || contents instanceof BasicComboPopup ) {
+				hideImpl();
+				return;
+			}
+
+			// defer hiding of heavy weight popup window for an event cycle,
+			// which allows reusing popup window to avoid flicker when "moving" popup
+			((JWindow)popupWindow).getContentPane().removeAll();
+			stillShownHeavyWeightPopups.add( this );
+			EventQueue.invokeLater( () -> {
+				// hide popup if it was not reused
+				if( stillShownHeavyWeightPopups.remove( this ) )
+					hideImpl();
+			} );
+		}
+
+		void hideImpl() {
 			if( contents instanceof JComponent )
 				((JComponent)contents).putClientProperty( KEY_POPUP_USES_NATIVE_BORDER, null );
 
 			if( delegate != null ) {
 				delegate.hide();
 				delegate = null;
+				owner = null;
 				contents = null;
 			}
 
@@ -557,6 +686,30 @@ public class FlatPopupFactory
 				popupWindow = null;
 			}
 		}
+
+		void reset( Component contents, int ownerX, int ownerY ) {
+			// update popup window location
+			popupWindow.setLocation( ownerX, ownerY );
+
+			// replace component in content pane
+			Container contentPane = ((JWindow)popupWindow).getContentPane();
+			contentPane.removeAll();
+			contentPane.add( contents, BorderLayout.CENTER );
+			popupWindow.invalidate();
+			popupWindow.validate();
+			popupWindow.pack();
+
+			// update client property on contents
+			if( this.contents != contents ) {
+				Object old = (this.contents instanceof JComponent)
+					? ((JComponent)this.contents).getClientProperty( KEY_POPUP_USES_NATIVE_BORDER )
+					: null;
+				if( contents instanceof JComponent )
+					((JComponent)contents).putClientProperty( KEY_POPUP_USES_NATIVE_BORDER, old );
+
+				this.contents = contents;
+			}
+		}
 	}
 
 	//---- class DropShadowPopup ----------------------------------------------
@@ -564,8 +717,6 @@ public class FlatPopupFactory
 	private class DropShadowPopup
 		extends NonFlashingPopup
 	{
-		private final Component owner;
-
 		// light weight
 		private JComponent lightComp;
 		private Border oldBorder;
@@ -580,11 +731,11 @@ public class FlatPopupFactory
 		// heavy weight
 		private Popup dropShadowDelegate;
 		private Window dropShadowWindow;
+		private JPanel dropShadowPanel2;
 		private Color oldDropShadowWindowBackground;
 
 		DropShadowPopup( Popup delegate, Component owner, Component contents ) {
-			super( delegate, contents );
-			this.owner = owner;
+			super( delegate, owner, contents );
 
 			Dimension size = contents.getPreferredSize();
 			if( size.width <= 0 || size.height <= 0 )
@@ -600,24 +751,24 @@ public class FlatPopupFactory
 				// the drop shadow and is positioned behind the popup window.
 
 				// create panel that paints the drop shadow
-				JPanel dropShadowPanel = new JPanel();
-				dropShadowPanel.setBorder( createDropShadowBorder() );
-				dropShadowPanel.setOpaque( false );
+				dropShadowPanel2 = new JPanel();
+				dropShadowPanel2.setBorder( createDropShadowBorder() );
+				dropShadowPanel2.setOpaque( false );
 
 				// set preferred size of drop shadow panel
 				Dimension prefSize = popupWindow.getPreferredSize();
-				Insets insets = dropShadowPanel.getInsets();
-				dropShadowPanel.setPreferredSize( new Dimension(
+				Insets insets = dropShadowPanel2.getInsets();
+				dropShadowPanel2.setPreferredSize( new Dimension(
 					prefSize.width + insets.left + insets.right,
 					prefSize.height + insets.top + insets.bottom ) );
 
 				// create heavy weight popup for drop shadow
 				int x = popupWindow.getX() - insets.left;
 				int y = popupWindow.getY() - insets.top;
-				dropShadowDelegate = getPopupForScreenOfOwner( owner, dropShadowPanel, x, y, true );
+				dropShadowDelegate = getPopupForScreenOfOwner( owner, dropShadowPanel2, x, y, true );
 
 				// make drop shadow popup window translucent
-				dropShadowWindow = SwingUtilities.windowForComponent( dropShadowPanel );
+				dropShadowWindow = SwingUtilities.windowForComponent( dropShadowPanel2 );
 				if( dropShadowWindow != null ) {
 					oldDropShadowWindowBackground = dropShadowWindow.getBackground();
 					dropShadowWindow.setBackground( new Color( 0, true ) );
@@ -654,6 +805,23 @@ public class FlatPopupFactory
 			}
 		}
 
+		private DropShadowPopup( DropShadowPopup reusePopup ) {
+			super( reusePopup );
+
+			// not necessary to clone fields used for light/medium weight popups
+
+			// heavy weight
+			dropShadowDelegate = reusePopup.dropShadowDelegate;
+			dropShadowWindow = reusePopup.dropShadowWindow;
+			dropShadowPanel2 = reusePopup.dropShadowPanel2;
+			oldDropShadowWindowBackground = reusePopup.oldDropShadowWindowBackground;
+		}
+
+		@Override
+		NonFlashingPopup cloneForReuse() {
+			return new DropShadowPopup( this );
+		}
+
 		private Border createDropShadowBorder() {
 			return new FlatDropShadowBorder(
 				UIManager.getColor( "Popup.dropShadowColor" ),
@@ -662,14 +830,14 @@ public class FlatPopupFactory
 		}
 
 		@Override
-		public void show() {
+		void showImpl() {
 			if( dropShadowDelegate != null )
 				showPopupAndFixLocation( dropShadowDelegate, dropShadowWindow );
 
 			if( mediumWeightPanel != null )
 				showMediumWeightDropShadow();
 
-			super.show();
+			super.showImpl();
 
 			// fix location of light weight popup in case it has left or top drop shadow
 			if( lightComp != null ) {
@@ -680,10 +848,11 @@ public class FlatPopupFactory
 		}
 
 		@Override
-		public void hide() {
+		void hideImpl() {
 			if( dropShadowDelegate != null ) {
 				dropShadowDelegate.hide();
 				dropShadowDelegate = null;
+				dropShadowPanel2 = null;
 			}
 
 			if( mediumWeightPanel != null ) {
@@ -692,7 +861,7 @@ public class FlatPopupFactory
 				mediumWeightPanel = null;
 			}
 
-			super.hide();
+			super.hideImpl();
 
 			if( dropShadowWindow != null ) {
 				dropShadowWindow.setBackground( oldDropShadowWindowBackground );
@@ -776,5 +945,25 @@ public class FlatPopupFactory
 			if( dropShadowPanel != null && mediumWeightPanel != null )
 				dropShadowPanel.setSize( FlatUIUtils.addInsets( mediumWeightPanel.getSize(), dropShadowPanel.getInsets() ) );
 		}
+
+		@Override
+		void reset( Component contents, int ownerX, int ownerY ) {
+			super.reset( contents, ownerX, ownerY );
+
+			if( dropShadowWindow != null ) {
+				// set preferred size of drop shadow panel
+				Dimension prefSize = popupWindow.getPreferredSize();
+				Insets insets = dropShadowPanel2.getInsets();
+				int w = prefSize.width + insets.left + insets.right;
+				int h = prefSize.height + insets.top + insets.bottom;
+				dropShadowPanel2.setPreferredSize( new Dimension( w, h ) );
+
+				// update drop shadow popup window location and size
+				int x = popupWindow.getX() - insets.left;
+				int y = popupWindow.getY() - insets.top;
+				dropShadowWindow.setBounds( x, y, w, h );
+				dropShadowWindow.pack();
+			}
+		}
 	}
 }

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatProgressBarUI.java

@@ -18,6 +18,7 @@ package com.formdev.flatlaf.ui;
 
 import static com.formdev.flatlaf.FlatClientProperties.*;
 import java.awt.Dimension;
+import java.awt.EventQueue;
 import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
@@ -86,6 +87,17 @@ public class FlatProgressBarUI
 		installStyle();
 	}
 
+	@Override
+	public void uninstallUI( JComponent c ) {
+		if( !EventQueue.isDispatchThread() && progressBar.isIndeterminate() ) {
+			LoggingFacade.INSTANCE.logSevere(
+				"FlatLaf: Uninstalling indeterminate progress bar UI not on AWT thread may throw NPE in FlatProgressBarUI.paint(). Use SwingUtilities.invokeLater().",
+				new IllegalStateException() );
+		}
+
+		super.uninstallUI( c );
+	}
+
 	@Override
 	protected void installDefaults() {
 		super.installDefaults();
@@ -110,17 +122,25 @@ public class FlatProgressBarUI
 
 		propertyChangeListener = e -> {
 			switch( e.getPropertyName() ) {
+				case "indeterminate":
+					if( !EventQueue.isDispatchThread() && !progressBar.isIndeterminate() ) {
+						LoggingFacade.INSTANCE.logSevere(
+							"FlatLaf: Using JProgressBar.setIndeterminate(false) not on AWT thread may throw NPE in FlatProgressBarUI.paint(). Use SwingUtilities.invokeLater().",
+							new IllegalStateException() );
+					}
+					break;
+
 				case PROGRESS_BAR_LARGE_HEIGHT:
 				case PROGRESS_BAR_SQUARE:
 					progressBar.revalidate();
-					progressBar.repaint();
+					HiDPIUtils.repaint( progressBar );
 					break;
 
 				case STYLE:
 				case STYLE_CLASS:
 					installStyle();
 					progressBar.revalidate();
-					progressBar.repaint();
+					HiDPIUtils.repaint( progressBar );
 					break;
 			}
 		};
@@ -274,6 +294,6 @@ public class FlatProgressBarUI
 		// Only solution is to repaint whole progress bar.
 		double systemScaleFactor = UIScale.getSystemScaleFactor( progressBar.getGraphicsConfiguration() );
 		if( (int) systemScaleFactor != systemScaleFactor )
-			progressBar.repaint();
+			HiDPIUtils.repaint( progressBar );
 	}
 }

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatRadioButtonMenuItemUI.java

@@ -23,6 +23,7 @@ import java.lang.invoke.MethodHandles;
 import java.util.Map;
 import javax.swing.Icon;
 import javax.swing.JComponent;
+import javax.swing.JMenuItem;
 import javax.swing.LookAndFeel;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicMenuItemUI;
@@ -102,13 +103,23 @@ public class FlatRadioButtonMenuItemUI
 		oldStyleValues = null;
 	}
 
+	@Override
+	protected void installComponents( JMenuItem menuItem ) {
+		super.installComponents( menuItem );
+
+		// update HTML renderer if necessary
+		FlatHTML.updateRendererCSSFontBaseSize( menuItem );
+	}
+
 	protected FlatMenuItemRenderer createRenderer() {
 		return new FlatMenuItemRenderer( menuItem, checkIcon, arrowIcon, acceleratorFont, acceleratorDelimiter );
 	}
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+		return FlatHTML.createPropertyChangeListener(
+			FlatStylingSupport.createPropertyChangeListener( c, this::installStyle,
+				super.createPropertyChangeListener( c ) ) );
 	}
 
 	/** @since 2 */

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatRadioButtonUI.java

@@ -40,12 +40,14 @@ import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicButtonListener;
+import javax.swing.plaf.basic.BasicHTML;
 import javax.swing.plaf.basic.BasicRadioButtonUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.icons.FlatCheckBoxIcon;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.ui.FlatStylingSupport.UnknownStyleException;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -159,6 +161,10 @@ public class FlatRadioButtonUI
 	/** @since 2 */
 	protected void propertyChange( AbstractButton b, PropertyChangeEvent e ) {
 		switch( e.getPropertyName() ) {
+			case BasicHTML.propertyKey:
+				FlatHTML.updateRendererCSSFontBaseSize( b );
+				break;
+
 			case FlatClientProperties.STYLE:
 			case FlatClientProperties.STYLE_CLASS:
 				if( shared && FlatStylingSupport.hasStyleProperty( b ) ) {
@@ -168,7 +174,7 @@ public class FlatRadioButtonUI
 				} else
 					installStyle( b );
 				b.revalidate();
-				b.repaint();
+				HiDPIUtils.repaint( b );
 				break;
 		}
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatRootPaneUI.java

@@ -270,6 +270,7 @@ public class FlatRootPaneUI
 	// layer title pane under frame content layer to allow placing menu bar over title pane
 	protected final static Integer TITLE_PANE_LAYER = JLayeredPane.FRAME_CONTENT_LAYER - 1;
 	private final static Integer TITLE_PANE_MOUSE_LAYER = JLayeredPane.FRAME_CONTENT_LAYER - 2;
+	private final static Integer WINDOW_TOP_BORDER_LAYER = Integer.MAX_VALUE;
 
 	// for fullWindowContent mode, layer title pane over frame content layer to allow placing title bar buttons over content
 	/** @since 3.4 */
@@ -285,11 +286,15 @@ public class FlatRootPaneUI
 		if( titlePane != null ) {
 			layeredPane.remove( titlePane );
 			layeredPane.remove( titlePane.mouseLayer );
+			if( titlePane.windowTopBorderLayer != null )
+				layeredPane.remove( titlePane.windowTopBorderLayer );
 		}
 
 		if( newTitlePane != null ) {
 			layeredPane.add( newTitlePane, getLayerForTitlePane() );
 			layeredPane.add( newTitlePane.mouseLayer, TITLE_PANE_MOUSE_LAYER );
+			if( newTitlePane.windowTopBorderLayer != null && newTitlePane.isWindowTopBorderNeeded() && isFullWindowContent( rootPane ) )
+				layeredPane.add( newTitlePane.windowTopBorderLayer, WINDOW_TOP_BORDER_LAYER );
 		}
 
 		titlePane = newTitlePane;
@@ -443,9 +448,21 @@ public class FlatRootPaneUI
 					titlePane.titleBarColorsChanged();
 				break;
 
+			case FlatClientProperties.TITLE_BAR_HEIGHT:
+				if( titlePane != null )
+					titlePane.revalidate();
+				break;
+
 			case FlatClientProperties.FULL_WINDOW_CONTENT:
 				if( titlePane != null ) {
 					rootPane.getLayeredPane().setLayer( titlePane, getLayerForTitlePane() );
+					if( titlePane.windowTopBorderLayer != null ) {
+						JLayeredPane layeredPane = rootPane.getLayeredPane();
+						if( titlePane.isWindowTopBorderNeeded() && isFullWindowContent( rootPane ) )
+							layeredPane.add( titlePane.windowTopBorderLayer, WINDOW_TOP_BORDER_LAYER );
+						else
+							layeredPane.remove( titlePane.windowTopBorderLayer );
+					}
 					titlePane.updateIcon();
 					titlePane.updateVisibility();
 					titlePane.updateFullWindowContentButtonsBoundsProperty();
@@ -591,6 +608,12 @@ public class FlatRootPaneUI
 					titlePane.setBounds( 0, 0, width, prefHeight );
 
 				titlePane.mouseLayer.setBounds( 0, 0, width, prefHeight );
+				if( titlePane.windowTopBorderLayer != null ) {
+					boolean show = isFullWindowContent && !titlePane.isWindowMaximized() && !isFullScreen;
+					if( show )
+						titlePane.windowTopBorderLayer.setBounds( 0, 0, width, 1 );
+					titlePane.windowTopBorderLayer.setVisible( show );
+				}
 
 				if( !isFullWindowContent )
 					nextY += prefHeight;

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollBarUI.java

@@ -43,6 +43,7 @@ import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableField;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableLookupProvider;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
@@ -212,14 +213,14 @@ public class FlatScrollBarUI
 			switch( e.getPropertyName() ) {
 				case FlatClientProperties.SCROLL_BAR_SHOW_BUTTONS:
 					scrollbar.revalidate();
-					scrollbar.repaint();
+					HiDPIUtils.repaint( scrollbar );
 					break;
 
 				case FlatClientProperties.STYLE:
 				case FlatClientProperties.STYLE_CLASS:
 					installStyle();
 					scrollbar.revalidate();
-					scrollbar.repaint();
+					HiDPIUtils.repaint( scrollbar );
 					break;
 
 				case "componentOrientation":
@@ -492,7 +493,7 @@ public class FlatScrollBarUI
 
 		private void repaint() {
 			if( scrollbar.isEnabled() )
-				scrollbar.repaint();
+				HiDPIUtils.repaint( scrollbar );
 		}
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatScrollPaneUI.java

@@ -55,6 +55,7 @@ import javax.swing.plaf.basic.BasicScrollPaneUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -209,7 +210,7 @@ public class FlatScrollPaneUI
 
 			// Use (0, 0) view position to obtain a constant unit increment of first item.
 			// Unit increment may be different for each item.
-			Rectangle visibleRect = new Rectangle( viewport.getViewSize() );
+			Rectangle visibleRect = new Rectangle( viewport.getExtentSize() );
 			unitIncrement = scrollable.getScrollableUnitIncrement( visibleRect, orientation, 1 );
 
 			if( unitIncrement > 0 ) {
@@ -297,11 +298,11 @@ public class FlatScrollPaneUI
 					JScrollBar hsb = scrollpane.getHorizontalScrollBar();
 					if( vsb != null ) {
 						vsb.revalidate();
-						vsb.repaint();
+						HiDPIUtils.repaint( vsb );
 					}
 					if( hsb != null ) {
 						hsb.revalidate();
-						hsb.repaint();
+						HiDPIUtils.repaint( hsb );
 					}
 					break;
 
@@ -321,14 +322,14 @@ public class FlatScrollPaneUI
 					break;
 
 				case FlatClientProperties.OUTLINE:
-					scrollpane.repaint();
+					HiDPIUtils.repaint( scrollpane );
 					break;
 
 				case FlatClientProperties.STYLE:
 				case FlatClientProperties.STYLE_CLASS:
 					installStyle();
 					scrollpane.revalidate();
-					scrollpane.repaint();
+					HiDPIUtils.repaint( scrollpane );
 					break;
 
 				case "border":
@@ -339,7 +340,7 @@ public class FlatScrollPaneUI
 						borderShared = null;
 						installStyle();
 						scrollpane.revalidate();
-						scrollpane.repaint();
+						HiDPIUtils.repaint( scrollpane );
 					}
 					break;
 			}
@@ -538,14 +539,14 @@ public class FlatScrollPaneUI
 		public void focusGained( FocusEvent e ) {
 			// necessary to update focus border
 			if( scrollpane.getBorder() instanceof FlatBorder )
-				scrollpane.repaint();
+				HiDPIUtils.repaint( scrollpane );
 		}
 
 		@Override
 		public void focusLost( FocusEvent e ) {
 			// necessary to update focus border
 			if( scrollpane.getBorder() instanceof FlatBorder )
-				scrollpane.repaint();
+				HiDPIUtils.repaint( scrollpane );
 		}
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSeparatorUI.java

@@ -32,6 +32,7 @@ import javax.swing.plaf.basic.BasicSeparatorUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 
 /**
@@ -134,7 +135,7 @@ public class FlatSeparatorUI
 				} else
 					installStyle( s );
 				s.revalidate();
-				s.repaint();
+				HiDPIUtils.repaint( s );
 				break;
 		}
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSliderUI.java

@@ -25,6 +25,8 @@ import java.awt.Graphics2D;
 import java.awt.Insets;
 import java.awt.Rectangle;
 import java.awt.Shape;
+import java.awt.event.FocusEvent;
+import java.awt.event.FocusListener;
 import java.awt.event.MouseEvent;
 import java.awt.geom.Ellipse2D;
 import java.awt.geom.Path2D;
@@ -191,6 +193,23 @@ public class FlatSliderUI
 		return new FlatTrackListener();
 	}
 
+	@Override
+	protected FocusListener createFocusListener( JSlider slider ) {
+		return new BasicSliderUI.FocusHandler() {
+			@Override
+			public void focusGained( FocusEvent e ) {
+				super.focusGained( e );
+				HiDPIUtils.repaint( slider );
+			}
+
+			@Override
+			public void focusLost( FocusEvent e ) {
+				super.focusLost( e );
+				HiDPIUtils.repaint( slider );
+			}
+		};
+	}
+
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JSlider slider ) {
 		return FlatStylingSupport.createPropertyChangeListener( slider, this::installStyle,
@@ -422,7 +441,7 @@ debug*/
 		Color thumbColor, Color thumbBorderColor, Color focusedColor, float thumbBorderWidth, int focusWidth )
 	{
 		double systemScaleFactor = UIScale.getSystemScaleFactor( (Graphics2D) g );
-		if( systemScaleFactor != 1 && systemScaleFactor != 2 ) {
+		if( systemScaleFactor != (int) systemScaleFactor ) {
 			// paint at scale 1x to avoid clipping on right and bottom edges at 125%, 150% or 175%
 			HiDPIUtils.paintAtScale1x( (Graphics2D) g, thumbRect.x, thumbRect.y, thumbRect.width, thumbRect.height,
 				(g2d, x2, y2, width2, height2, scaleFactor) -> {
@@ -579,15 +598,15 @@ debug*/
 
 	@Override
 	public void setThumbLocation( int x, int y ) {
-		if( !isRoundThumb() ) {
-			// the needle of the directional thumb is painted outside of thumbRect
-			// --> must increase repaint rectangle
-
 		// set new thumb location and compute union of old and new thumb bounds
 		Rectangle r = new Rectangle( thumbRect );
 		thumbRect.setLocation( x, y );
 		SwingUtilities.computeUnion( thumbRect.x, thumbRect.y, thumbRect.width, thumbRect.height, r );
 
+		if( !isRoundThumb() ) {
+			// the needle of the directional thumb is painted outside of thumbRect
+			// --> must increase repaint rectangle
+
 			// increase union rectangle for repaint
 			int extra = (int) Math.ceil( UIScale.scale( focusWidth ) * 0.4142f );
 			if( slider.getOrientation() == JSlider.HORIZONTAL )
@@ -597,10 +616,9 @@ debug*/
 				if( !slider.getComponentOrientation().isLeftToRight() )
 					r.x -= extra;
 			}
+		}
 
-			slider.repaint( r );
-		} else
-			super.setThumbLocation( x, y );
+		HiDPIUtils.repaint( slider, r );
 	}
 
 	//---- class FlatTrackListener --------------------------------------------
@@ -688,21 +706,21 @@ debug*/
 				!UIManager.getBoolean( "Slider.snapToTicksOnReleased" ) )
 			{
 				calculateThumbLocation();
-				slider.repaint();
+				HiDPIUtils.repaint( slider );
 			}
 		}
 
 		protected void setThumbHover( boolean hover ) {
 			if( hover != thumbHover ) {
 				thumbHover = hover;
-				slider.repaint( thumbRect );
+				HiDPIUtils.repaint( slider, thumbRect );
 			}
 		}
 
 		protected void setThumbPressed( boolean pressed ) {
 			if( pressed != thumbPressed ) {
 				thumbPressed = pressed;
-				slider.repaint( thumbRect );
+				HiDPIUtils.repaint( slider, thumbRect );
 			}
 		}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSpinnerUI.java

@@ -47,6 +47,7 @@ import javax.swing.plaf.basic.BasicSpinnerUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 
 /**
@@ -586,7 +587,7 @@ public class FlatSpinnerUI
 		@Override
 		public void focusGained( FocusEvent e ) {
 			// necessary to update focus border
-			spinner.repaint();
+			HiDPIUtils.repaint( spinner );
 
 			// if spinner gained focus, transfer it to the editor text field
 			if( e.getComponent() == spinner ) {
@@ -599,7 +600,7 @@ public class FlatSpinnerUI
 		@Override
 		public void focusLost( FocusEvent e ) {
 			// necessary to update focus border
-			spinner.repaint();
+			HiDPIUtils.repaint( spinner );
 		}
 
 		//---- interface PropertyChangeListener ----
@@ -614,7 +615,7 @@ public class FlatSpinnerUI
 
 				case FlatClientProperties.COMPONENT_ROUND_RECT:
 				case FlatClientProperties.OUTLINE:
-					spinner.repaint();
+					HiDPIUtils.repaint( spinner );
 					break;
 
 				case FlatClientProperties.MINIMUM_WIDTH:
@@ -625,7 +626,7 @@ public class FlatSpinnerUI
 				case FlatClientProperties.STYLE_CLASS:
 					installStyle();
 					spinner.revalidate();
-					spinner.repaint();
+					HiDPIUtils.repaint( spinner );
 					break;
 			}
 		}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSplitPaneUI.java

@@ -301,6 +301,10 @@ public class FlatSplitPaneUI
 					// necessary to show/hide one-touch buttons on expand/collapse
 					doLayout();
 					break;
+
+				case FlatClientProperties.SPLIT_PANE_EXPANDABLE_SIDE:
+					revalidate();
+					break;
 			}
 		}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatStylingSupport.java

@@ -40,6 +40,7 @@ import javax.swing.UIManager;
 import javax.swing.border.Border;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.FlatLaf;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.StringUtils;
 import com.formdev.flatlaf.util.SystemInfo;
 
@@ -709,7 +710,7 @@ public class FlatStylingSupport
 				case FlatClientProperties.STYLE_CLASS:
 					installStyle.run();
 					c.revalidate();
-					c.repaint();
+					HiDPIUtils.repaint( c );
 					break;
 			}
 		};

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTabbedPaneUI.java

@@ -98,6 +98,7 @@ import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.ui.FlatStylingSupport.UnknownStyleException;
 import com.formdev.flatlaf.util.Animator;
 import com.formdev.flatlaf.util.CubicBezierEasing;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.JavaCompatibility;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.StringUtils;
@@ -895,7 +896,7 @@ public class FlatTabbedPaneUI
 			}
 		}
 
-		tabPane.repaint( r );
+		HiDPIUtils.repaint( tabPane, r );
 	}
 
 	private boolean inCalculateEqual;
@@ -1684,7 +1685,7 @@ debug*/
 			w - (ci.left / 100f) - (ci.right / 100f), h - (ci.top / 100f) - (ci.bottom / 100f) ), false );
 
 		// add gap for selected tab to path
-		if( getTabType() == TAB_TYPE_CARD ) {
+		if( getTabType() == TAB_TYPE_CARD && selectedIndex >= 0 ) {
 			float csh = scale( (float) contentSeparatorHeight );
 
 			Rectangle tabRect = getTabBounds( tabPane, selectedIndex );
@@ -2581,19 +2582,19 @@ debug*/
 		@Override
 		public void popupMenuWillBecomeVisible( PopupMenuEvent e ) {
 			popupVisible = true;
-			repaint();
+			HiDPIUtils.repaint( this );
 		}
 
 		@Override
 		public void popupMenuWillBecomeInvisible( PopupMenuEvent e ) {
 			popupVisible = false;
-			repaint();
+			HiDPIUtils.repaint( this );
 		}
 
 		@Override
 		public void popupMenuCanceled( PopupMenuEvent e ) {
 			popupVisible = false;
-			repaint();
+			HiDPIUtils.repaint( this );
 		}
 	}
 
@@ -3102,7 +3103,7 @@ debug*/
 
 				case TABBED_PANE_SHOW_TAB_SEPARATORS:
 				case TABBED_PANE_TAB_TYPE:
-					tabPane.repaint();
+					HiDPIUtils.repaint( tabPane );
 					break;
 
 				case TABBED_PANE_SHOW_CONTENT_SEPARATOR:
@@ -3125,14 +3126,14 @@ debug*/
 				case TABBED_PANE_TAB_ICON_PLACEMENT:
 				case TABBED_PANE_TAB_CLOSABLE:
 					tabPane.revalidate();
-					tabPane.repaint();
+					HiDPIUtils.repaint( tabPane );
 					break;
 
 				case TABBED_PANE_LEADING_COMPONENT:
 					uninstallLeadingComponent();
 					installLeadingComponent();
 					tabPane.revalidate();
-					tabPane.repaint();
+					HiDPIUtils.repaint( tabPane );
 					ensureSelectedTabIsVisibleLater();
 					break;
 
@@ -3140,7 +3141,7 @@ debug*/
 					uninstallTrailingComponent();
 					installTrailingComponent();
 					tabPane.revalidate();
-					tabPane.repaint();
+					HiDPIUtils.repaint( tabPane );
 					ensureSelectedTabIsVisibleLater();
 					break;
 
@@ -3148,7 +3149,7 @@ debug*/
 				case STYLE_CLASS:
 					installStyle();
 					tabPane.revalidate();
-					tabPane.repaint();
+					HiDPIUtils.repaint( tabPane );
 					break;
 			}
 		}
@@ -3172,7 +3173,7 @@ debug*/
 				case TABBED_PANE_TAB_ALIGNMENT:
 				case TABBED_PANE_TAB_CLOSABLE:
 					tabPane.revalidate();
-					tabPane.repaint();
+					HiDPIUtils.repaint( tabPane );
 					break;
 			}
 		}
@@ -3767,9 +3768,20 @@ debug*/
 			boolean hideDisabledScrollButtons = (scrollButtonsPolicy == AS_NEEDED_SINGLE && scrollButtonsPlacement == BOTH);
 			boolean trailingScrollButtons = (scrollButtonsPlacement == TRAILING);
 
-			// for right-to-left always use "more tabs" button for horizontal scrolling
+			// For right-to-left, always use "more tabs" button for horizontal scrolling
 			// because methods scrollForward() and scrollBackward() in class
-			// BasicTabbedPaneUI.ScrollableTabSupport do not work for right-to-left
+			// BasicTabbedPaneUI.ScrollableTabSupport do not work for right-to-left.
+			//
+			// One problem is that BasicTabbedPaneUI.getClosestTab(), which is used
+			// to compute leadingTabIndex, does not work for right-to-left because is uses "binary" search
+			// on rects[] to find tab, but rects[] is ordered in reverse order for right-to-left.
+			// So leadingTabIndex is either zero or tabCount.
+			// Therefore increasing/decreasing leadingTabIndex in scrollForward()
+			// and scrollBackward() does not work as expected.
+			// Also backward/forward scroll buttons are not correctly enabled/disabled.
+			//
+			// Fixing this would require replacing nearly whole functionality of class
+			// BasicTabbedPaneUI.ScrollableTabSupport, which is not possible because it is private.
 			boolean leftToRight = isLeftToRight();
 			if( !leftToRight && isHorizontalTabPlacement( tabPane.getTabPlacement() ) ) {
 				useMoreTabsButton = true;
@@ -3851,6 +3863,8 @@ debug*/
 							w -= buttonWidth;
 							moreTabsButtonVisible = true;
 						}
+
+						// layout scroll buttons
 						if( useScrollButtons ) {
 							// the tabViewport view size is set in
 							// BasicTabbedPaneUI.TabbedPaneScrollLayout.calculateTabRects(),
@@ -3858,30 +3872,28 @@ debug*/
 							Point viewPosition = tabViewport.getViewPosition();
 							Dimension viewSize = tabViewport.getViewSize();
 
+							// layout forward button on trailing side
+							if( !hideDisabledScrollButtons || viewSize.width - viewPosition.x > w ) {
+								int buttonWidth = forwardButton.getPreferredSize().width;
+								forwardButton.setBounds( x + w - buttonWidth, y, buttonWidth, h );
+								w -= buttonWidth;
+								forwardButtonVisible = true;
+							}
+
 							// layout backward button
 							if( !hideDisabledScrollButtons || viewPosition.x > 0 ) {
 								int buttonWidth = backwardButton.getPreferredSize().width;
 								if( trailingScrollButtons ) {
 									// on trailing side
-									backwardButton.setBounds( leftToRight ? (x + w - buttonWidth) : x, y, buttonWidth, h );
-									x += leftToRight ? 0 : buttonWidth;
+									backwardButton.setBounds( x + w - buttonWidth, y, buttonWidth, h );
 								} else {
 									// on leading side
-									backwardButton.setBounds( leftToRight ? x : (x + w - buttonWidth), y, buttonWidth, h );
-									x += leftToRight ? buttonWidth : 0;
+									backwardButton.setBounds( x, y, buttonWidth, h );
+									x += buttonWidth;
 								}
 								w -= buttonWidth;
 								backwardButtonVisible = true;
 							}
-
-							// layout forward button on trailing side
-							if( !hideDisabledScrollButtons || viewSize.width - viewPosition.x > w ) {
-								int buttonWidth = forwardButton.getPreferredSize().width;
-								forwardButton.setBounds( leftToRight ? (x + w - buttonWidth) : x, y, buttonWidth, h );
-								x += leftToRight ? 0 : buttonWidth;
-								w -= buttonWidth;
-								forwardButtonVisible = true;
-							}
 						}
 					}
 
@@ -3927,6 +3939,8 @@ debug*/
 							h -= buttonHeight;
 							moreTabsButtonVisible = true;
 						}
+
+						// layout scroll buttons
 						if( useScrollButtons ) {
 							// the tabViewport view size is set in
 							// BasicTabbedPaneUI.TabbedPaneScrollLayout.calculateTabRects(),
@@ -3934,6 +3948,14 @@ debug*/
 							Point viewPosition = tabViewport.getViewPosition();
 							Dimension viewSize = tabViewport.getViewSize();
 
+							// layout forward button on bottom side
+							if( !hideDisabledScrollButtons || viewSize.height - viewPosition.y > h ) {
+								int buttonHeight = forwardButton.getPreferredSize().height;
+								forwardButton.setBounds( x, y + h - buttonHeight, w, buttonHeight );
+								h -= buttonHeight;
+								forwardButtonVisible = true;
+							}
+
 							// layout backward button
 							if( !hideDisabledScrollButtons || viewPosition.y > 0 ) {
 								int buttonHeight = backwardButton.getPreferredSize().height;
@@ -3948,14 +3970,6 @@ debug*/
 								h -= buttonHeight;
 								backwardButtonVisible = true;
 							}
-
-							// layout forward button on bottom side
-							if( !hideDisabledScrollButtons || viewSize.height - viewPosition.y > h ) {
-								int buttonHeight = forwardButton.getPreferredSize().height;
-								forwardButton.setBounds( x, y + h - buttonHeight, w, buttonHeight );
-								h -= buttonHeight;
-								forwardButtonVisible = true;
-							}
 						}
 					}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTableCellBorder.java

@@ -65,8 +65,28 @@ public class FlatTableCellBorder
 		return super.getLineColor();
 	}
 
+	@Override
+	public int getArc() {
+		if( c != null ) {
+			Integer selectionArc = getStyleFromTableUI( c, ui -> ui.selectionArc );
+			if( selectionArc != null )
+				return selectionArc;
+		}
+		return super.getArc();
+	}
+
 	@Override
 	public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+		if( c != null ) {
+			Insets selectionInsets = getStyleFromTableUI( c, ui -> ui.selectionInsets );
+			if( selectionInsets != null ) {
+				x += selectionInsets.left;
+				y += selectionInsets.top;
+				width -= selectionInsets.left + selectionInsets.right;
+				height -= selectionInsets.top + selectionInsets.bottom;
+			}
+		}
+
 		this.c = c;
 		super.paintBorder( c, g, x, y, width, height );
 		this.c = null;

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTableHeaderUI.java

@@ -45,6 +45,7 @@ import javax.swing.table.TableColumn;
 import javax.swing.table.TableColumnModel;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -234,8 +235,8 @@ public class FlatTableHeaderUI
 
 	@Override
 	protected void rolloverColumnUpdated( int oldColumn, int newColumn ) {
-		header.repaint( header.getHeaderRect( oldColumn ) );
-		header.repaint( header.getHeaderRect( newColumn ) );
+		HiDPIUtils.repaint( header, header.getHeaderRect( oldColumn ) );
+		HiDPIUtils.repaint( header, header.getHeaderRect( newColumn ) );
 	}
 
 	@Override

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTableUI.java

@@ -24,7 +24,13 @@ import java.awt.EventQueue;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.Shape;
 import java.awt.event.ActionEvent;
+import java.awt.event.ComponentAdapter;
+import java.awt.event.ComponentEvent;
+import java.awt.event.ComponentListener;
 import java.awt.event.FocusEvent;
 import java.awt.event.FocusListener;
 import java.awt.geom.Rectangle2D;
@@ -38,21 +44,29 @@ import javax.swing.JScrollPane;
 import javax.swing.JTable;
 import javax.swing.JTextField;
 import javax.swing.JViewport;
+import javax.swing.ListSelectionModel;
 import javax.swing.LookAndFeel;
 import javax.swing.SwingConstants;
 import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ListSelectionEvent;
+import javax.swing.event.ListSelectionListener;
+import javax.swing.event.TableColumnModelEvent;
+import javax.swing.event.TableColumnModelListener;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.UIResource;
 import javax.swing.plaf.basic.BasicTableUI;
 import javax.swing.table.DefaultTableCellRenderer;
 import javax.swing.table.JTableHeader;
 import javax.swing.table.TableCellRenderer;
+import javax.swing.table.TableColumnModel;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.icons.FlatCheckBoxIcon;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.util.Graphics2DProxy;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
@@ -92,6 +106,8 @@ import com.formdev.flatlaf.util.UIScale;
  * @uiDefault Table.intercellSpacing					Dimension
  * @uiDefault Table.selectionInactiveBackground			Color
  * @uiDefault Table.selectionInactiveForeground			Color
+ * @uiDefault Table.selectionInsets						Insets
+ * @uiDefault Table.selectionArc						int
  * @uiDefault Table.paintOutsideAlternateRows			boolean
  * @uiDefault Table.editorSelectAllOnStartEditing		boolean
  *
@@ -120,6 +136,8 @@ public class FlatTableUI
 	@Styleable protected Color selectionForeground;
 	@Styleable protected Color selectionInactiveBackground;
 	@Styleable protected Color selectionInactiveForeground;
+	/** @since 3.5 */ @Styleable protected Insets selectionInsets;
+	/** @since 3.5 */ @Styleable protected int selectionArc;
 
 	// for FlatTableCellBorder
 	/** @since 2 */ @Styleable protected Insets cellMargins;
@@ -132,6 +150,9 @@ public class FlatTableUI
 	private TableCellRenderer oldBooleanRenderer;
 
 	private PropertyChangeListener propertyChangeListener;
+	private ComponentListener outsideAlternateRowsListener;
+	private ListSelectionListener rowSelectionListener;
+	private TableColumnModelListener columnSelectionListener;
 	private Map<String, Object> oldStyleValues;
 
 	public static ComponentUI createUI( JComponent c ) {
@@ -158,6 +179,8 @@ public class FlatTableUI
 		selectionForeground = UIManager.getColor( "Table.selectionForeground" );
 		selectionInactiveBackground = UIManager.getColor( "Table.selectionInactiveBackground" );
 		selectionInactiveForeground = UIManager.getColor( "Table.selectionInactiveForeground" );
+		selectionInsets = UIManager.getInsets( "Table.selectionInsets" );
+		selectionArc = UIManager.getInt( "Table.selectionArc" );
 
 		toggleSelectionColors();
 
@@ -245,6 +268,28 @@ public class FlatTableUI
 
 		propertyChangeListener = e -> {
 			switch( e.getPropertyName() ) {
+				case "selectionModel":
+					if( rowSelectionListener != null ) {
+						Object oldModel = e.getOldValue();
+						Object newModel = e.getNewValue();
+						if( oldModel != null )
+							((ListSelectionModel)oldModel).removeListSelectionListener( rowSelectionListener );
+						if( newModel != null )
+							((ListSelectionModel)newModel).addListSelectionListener( rowSelectionListener );
+					}
+					break;
+
+				case "columnModel":
+					if( columnSelectionListener != null ) {
+						Object oldModel = e.getOldValue();
+						Object newModel = e.getNewValue();
+						if( oldModel != null )
+							((TableColumnModel)oldModel).removeColumnModelListener( columnSelectionListener );
+						if( newModel != null )
+							((TableColumnModel)newModel).addColumnModelListener( columnSelectionListener );
+					}
+					break;
+
 				case FlatClientProperties.COMPONENT_FOCUS_OWNER:
 					toggleSelectionColors();
 					break;
@@ -253,11 +298,14 @@ public class FlatTableUI
 				case FlatClientProperties.STYLE_CLASS:
 					installStyle();
 					table.revalidate();
-					table.repaint();
+					HiDPIUtils.repaint( table );
 					break;
 			}
 		};
 		table.addPropertyChangeListener( propertyChangeListener );
+
+		if( selectionArc > 0 )
+			installRepaintRoundedSelectionListeners();
 	}
 
 	@Override
@@ -266,6 +314,19 @@ public class FlatTableUI
 
 		table.removePropertyChangeListener( propertyChangeListener );
 		propertyChangeListener = null;
+
+		if( outsideAlternateRowsListener != null ) {
+			table.removeComponentListener( outsideAlternateRowsListener );
+			outsideAlternateRowsListener = null;
+		}
+		if( rowSelectionListener != null ) {
+			table.getSelectionModel().removeListSelectionListener( rowSelectionListener );
+			rowSelectionListener = null;
+		}
+		if( columnSelectionListener != null ) {
+			table.getColumnModel().removeColumnModelListener( columnSelectionListener );
+			columnSelectionListener = null;
+		}
 	}
 
 	@Override
@@ -342,6 +403,8 @@ public class FlatTableUI
 	protected Object applyStyleProperty( String key, Object value ) {
 		if( "rowHeight".equals( key ) && value instanceof Integer )
 			value = UIScale.scale( (Integer) value );
+		else if( "selectionArc".equals( key ) && value instanceof Integer && (Integer) value > 0 )
+			installRepaintRoundedSelectionListeners();
 
 		return FlatStylingSupport.applyToAnnotatedObjectOrComponent( this, table, key, value );
 	}
@@ -404,6 +467,7 @@ public class FlatTableUI
 
 			double systemScaleFactor = UIScale.getSystemScaleFactor( (Graphics2D) g );
 			double lineThickness = (1. / systemScaleFactor) * (int) systemScaleFactor;
+			double lineOffset = (1. - lineThickness) + 0.05; // adding 0.05 to fix line location in some cases
 
 			// Java 8 uses drawLine() to paint grid lines
 			// Java 9+ uses fillRect() to paint grid lines (except for dragged column)
@@ -446,11 +510,11 @@ public class FlatTableUI
 					// reduce line thickness to avoid unstable painted line thickness
 					if( lineThickness != 1 ) {
 						if( horizontalLines && height == 1 && wasInvokedFromPaintGrid() ) {
-							super.fill( new Rectangle2D.Double( x, y, width, lineThickness ) );
+							super.fill( new Rectangle2D.Double( x, y + lineOffset, width, lineThickness ) );
 							return;
 						}
 						if( verticalLines && width == 1 && y == 0 && wasInvokedFromPaintGrid() ) {
-							super.fill( new Rectangle2D.Double( x, y, lineThickness, height ) );
+							super.fill( new Rectangle2D.Double( x + lineOffset, y, lineThickness, height ) );
 							return;
 						}
 					}
@@ -468,6 +532,10 @@ public class FlatTableUI
 			};
 		}
 
+		// rounded selection or selection insets
+		if( selectionArc > 0 || (selectionInsets != null && !FlatUIUtils.isInsetsEmpty( selectionInsets )) )
+			g = new RoundedSelectionGraphics( g, UIManager.getColor( "Table.alternateRowColor" ) );
+
 		super.paint( g, c );
 	}
 
@@ -513,8 +581,6 @@ public class FlatTableUI
 		boolean paintOutside = UIManager.getBoolean( "Table.paintOutsideAlternateRows" );
 		Color alternateColor;
 		if( paintOutside && (alternateColor = UIManager.getColor( "Table.alternateRowColor" )) != null ) {
-			g.setColor( alternateColor );
-
 			int rowCount = table.getRowCount();
 
 			// paint alternating empty rows below the table
@@ -523,10 +589,350 @@ public class FlatTableUI
 				int tableWidth = table.getWidth();
 				int rowHeight = table.getRowHeight();
 
+				g.setColor( alternateColor );
+
+				int x = viewport.getComponentOrientation().isLeftToRight() ? 0 : viewportWidth - tableWidth;
 				for( int y = tableHeight, row = rowCount; y < viewportHeight; y += rowHeight, row++ ) {
 					if( row % 2 != 0 )
-						g.fillRect( 0, y, tableWidth, rowHeight );
+						paintAlternateRowBackground( g, -1, -1, x, y, tableWidth, rowHeight );
 				}
+
+				// add listener on demand
+				if( outsideAlternateRowsListener == null && table.getAutoResizeMode() == JTable.AUTO_RESIZE_OFF ) {
+					outsideAlternateRowsListener = new FlatOutsideAlternateRowsListener();
+					table.addComponentListener( outsideAlternateRowsListener );
+				}
+			}
+		}
+	}
+
+	/**
+	 * Paints (rounded) alternate row background.
+	 * Supports {@link #selectionArc} and {@link #selectionInsets}.
+	 * <p>
+	 * <b>Note:</b> This method is only invoked if either selection arc
+	 *              is greater than zero or if selection insets are not empty.
+	 *
+	 * @since 3.5
+	 */
+	protected void paintAlternateRowBackground( Graphics g, int row, int column, int x, int y, int width, int height ) {
+		Insets insets = (selectionInsets != null) ? (Insets) selectionInsets.clone() : null;
+		float arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight;
+		arcTopLeft = arcTopRight = arcBottomLeft = arcBottomRight = UIScale.scale( selectionArc / 2f );
+
+		if( column >= 0 ) {
+			// selection insets
+
+			// selection arc
+			if( column > 0 ) {
+				if( insets != null )
+					insets.left = 0;
+
+				if( table.getComponentOrientation().isLeftToRight() )
+					arcTopLeft = arcBottomLeft = 0;
+				else
+					arcTopRight = arcBottomRight = 0;
+			}
+			if( column < table.getColumnCount() - 1 ) {
+				if( insets != null )
+					insets.right = 0;
+
+				if( table.getComponentOrientation().isLeftToRight() )
+					arcTopRight = arcBottomRight = 0;
+				else
+					arcTopLeft = arcBottomLeft = 0;
+			}
+		}
+
+		FlatUIUtils.paintSelection( (Graphics2D) g, x, y, width, height,
+			UIScale.scale( insets ), arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight, 0 );
+	}
+
+	/**
+	 * Paints (rounded) cell selection.
+	 * Supports {@link #selectionArc} and {@link #selectionInsets}.
+	 * <p>
+	 * <b>Note:</b> This method is only invoked if either selection arc
+	 *              is greater than zero or if selection insets are not empty.
+	 *
+	 * @since 3.5
+	 */
+	protected void paintCellSelection( Graphics g, int row, int column, int x, int y, int width, int height ) {
+		boolean rowSelAllowed = table.getRowSelectionAllowed();
+		boolean colSelAllowed = table.getColumnSelectionAllowed();
+		boolean rowSelOnly = rowSelAllowed && !colSelAllowed;
+		boolean colSelOnly = colSelAllowed && !rowSelAllowed;
+		boolean cellOnlySel = rowSelAllowed && colSelAllowed;
+
+		// get selection state of surrounding cells
+		boolean leftSelected    = (column > 0 && (rowSelOnly || table.isCellSelected( row, column - 1 )));
+		boolean topSelected     = (row    > 0 && (colSelOnly || table.isCellSelected( row - 1, column )));
+		boolean rightSelected   = (column < table.getColumnCount() - 1 && (rowSelOnly || table.isCellSelected( row, column + 1 )));
+		boolean bottomSelected  = (row    < table.getRowCount() - 1    && (colSelOnly || table.isCellSelected( row + 1, column )));
+		if( !table.getComponentOrientation().isLeftToRight() ) {
+			boolean temp = leftSelected;
+			leftSelected = rightSelected;
+			rightSelected = temp;
+		}
+
+		// selection insets
+		// (insets are applied to whole row if row-only selection is used,
+		//  or to whole column if column-only selection is used,
+		//  or to cell if cell selection is used)
+		Insets insets = (selectionInsets != null) ? (Insets) selectionInsets.clone() : null;
+		if( insets != null ) {
+			if( rowSelOnly && leftSelected )
+				insets.left = 0;
+			if( rowSelOnly && rightSelected )
+				insets.right = 0;
+			if( colSelOnly && topSelected )
+				insets.top = 0;
+			if( colSelOnly && bottomSelected )
+				insets.bottom = 0;
+		}
+
+		// selection arc
+		float arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight;
+		arcTopLeft = arcTopRight = arcBottomLeft = arcBottomRight = UIScale.scale( selectionArc / 2f );
+		if( selectionArc > 0 ) {
+			// note that intercellSpacing is not considered as a gap because
+			// grid lines are usually painted to intercell space
+			boolean hasRowGap = (rowSelOnly || cellOnlySel) && insets != null && (insets.top != 0 || insets.bottom != 0);
+			boolean hasColGap = (colSelOnly || cellOnlySel) && insets != null && (insets.left != 0 || insets.right != 0);
+
+			if( leftSelected && !hasColGap )
+				arcTopLeft = arcBottomLeft = 0;
+			if( rightSelected && !hasColGap )
+				arcTopRight = arcBottomRight = 0;
+			if( topSelected && !hasRowGap )
+				arcTopLeft = arcTopRight = 0;
+			if( bottomSelected && !hasRowGap )
+				arcBottomLeft = arcBottomRight = 0;
+		}
+
+		FlatUIUtils.paintSelection( (Graphics2D) g, x, y, width, height,
+			UIScale.scale( insets ), arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight, 0 );
+	}
+
+	/**
+	 * Paints a cell selection at the given coordinates.
+	 * The selection color must be set on the graphics context.
+	 * <p>
+	 * This method is intended for use in custom cell renderers to support
+	 * {@link #selectionArc} and {@link #selectionInsets}.
+	 *
+	 * @since 3.5
+	 */
+	public static void paintCellSelection( JTable table, Graphics g, int row, int column, int x, int y, int width, int height ) {
+		if( !(table.getUI() instanceof FlatTableUI) )
+			return;
+
+		FlatTableUI ui = (FlatTableUI) table.getUI();
+		ui.paintCellSelection( g, row, column, x, y, width, height );
+	}
+
+	private void installRepaintRoundedSelectionListeners() {
+		if( rowSelectionListener == null ) {
+			rowSelectionListener = this::repaintRoundedRowSelection;
+			table.getSelectionModel().addListSelectionListener( rowSelectionListener );
+		}
+
+		if( columnSelectionListener == null ) {
+			columnSelectionListener = new TableColumnModelListener() {
+				@Override
+				public void columnSelectionChanged( ListSelectionEvent e ) {
+					repaintRoundedColumnSelection( e );
+				}
+				@Override public void columnRemoved( TableColumnModelEvent e ) {}
+				@Override public void columnMoved( TableColumnModelEvent e ) {}
+				@Override public void columnMarginChanged( ChangeEvent e ) {}
+				@Override public void columnAdded( TableColumnModelEvent e ) {}
+			};
+			table.getColumnModel().addColumnModelListener( columnSelectionListener );
+		}
+	}
+
+	private void repaintRoundedRowSelection( ListSelectionEvent e ) {
+		if( selectionArc <= 0 || !table.getRowSelectionAllowed() )
+			return;
+
+		int rowCount = table.getRowCount();
+		int columnCount = table.getColumnCount();
+		if( rowCount <= 0 || columnCount <= 0 )
+			return;
+
+		// repaint including rows before and after changed selection
+		int firstRow = Math.max( 0, Math.min( e.getFirstIndex() - 1, rowCount - 1 ) );
+		int lastRow = Math.max( 0, Math.min( e.getLastIndex() + 1, rowCount - 1 ) );
+		Rectangle firstRect = table.getCellRect( firstRow, 0, false );
+		Rectangle lastRect = table.getCellRect( lastRow, columnCount - 1, false );
+		table.repaint( firstRect.union( lastRect ) );
+	}
+
+	private void repaintRoundedColumnSelection( ListSelectionEvent e ) {
+		if( selectionArc <= 0 || !table.getColumnSelectionAllowed() )
+			return;
+
+		int rowCount = table.getRowCount();
+		int columnCount = table.getColumnCount();
+		if( rowCount <= 0 || columnCount <= 0 )
+			return;
+
+		// limit to selected rows for cell selection
+		int firstRow = 0;
+		int lastRow = rowCount - 1;
+		if( table.getRowSelectionAllowed() ) {
+			firstRow = table.getSelectionModel().getMinSelectionIndex();
+			lastRow = table.getSelectionModel().getMaxSelectionIndex();
+		}
+
+		// repaint including columns before and after changed selection
+		int firstColumn = Math.max( 0, Math.min( e.getFirstIndex() - 1, columnCount - 1 ) );
+		int lastColumn = Math.max( 0, Math.min( e.getLastIndex() + 1, columnCount - 1 ) );
+		Rectangle firstRect = table.getCellRect( firstRow, firstColumn, false );
+		Rectangle lastRect = table.getCellRect( lastRow, lastColumn, false );
+		table.repaint( firstRect.union( lastRect ) );
+	}
+
+	//---- class RoundedSelectionGraphics -------------------------------------
+
+	/**
+	 * Because selection painting is done in the cell renderer, it would be
+	 * necessary to require a FlatLaf specific renderer to implement rounded selection.
+	 * Using a LaF specific renderer was avoided because often a custom renderer is
+	 * already used in applications. Then either the rounded selection is not used,
+	 * or the application has to be changed to extend a FlatLaf renderer.
+	 * <p>
+	 * To solve this, a graphics proxy is used that paints rounded selection
+	 * if row/column/cell is selected and the renderer wants to fill the background.
+	 */
+	private class RoundedSelectionGraphics
+		extends Graphics2DProxy
+	{
+		private final Color alternateRowColor;
+
+		// used to avoid endless loop in case that paintCellSelection() invokes
+		// g.fillRect() with full bounds (selectionInsets is 0,0,0,0)
+		private boolean inPaintSelection;
+
+		RoundedSelectionGraphics( Graphics delegate, Color alternateRowColor ) {
+			super( (Graphics2D) delegate );
+			this.alternateRowColor = alternateRowColor;
+		}
+
+		@Override
+		public Graphics create() {
+			return new RoundedSelectionGraphics( super.create(), alternateRowColor );
+		}
+
+		@Override
+		public Graphics create( int x, int y, int width, int height ) {
+			return new RoundedSelectionGraphics( super.create( x, y, width, height ), alternateRowColor );
+		}
+
+		@Override
+		public void fillRect( int x, int y, int width, int height ) {
+			if( fillCellSelection( x, y, width, height ) )
+				return;
+
+			super.fillRect( x, y, width, height );
+		}
+
+		@Override
+		public void fill( Shape shape ) {
+			if( shape instanceof Rectangle2D ) {
+				Rectangle2D r = (Rectangle2D) shape;
+				double x = r.getX();
+				double y = r.getY();
+				double width = r.getWidth();
+				double height = r.getHeight();
+				if( x == (int) x && y == (int) y && width == (int) width && height == (int) height ) {
+					if( fillCellSelection( (int) x, (int) y, (int) width, (int) height ) )
+						return;
+				}
+			}
+
+			super.fill( shape );
+		}
+
+		private boolean fillCellSelection( int x, int y, int width, int height ) {
+			if( inPaintSelection )
+				return false;
+
+			Color color;
+			Component rendererComponent;
+			if( x == 0 && y == 0 &&
+				((color = getColor()) == table.getSelectionBackground() ||
+				 (alternateRowColor != null && color == alternateRowColor)) &&
+				(rendererComponent = findActiveRendererComponent()) != null &&
+				width == rendererComponent.getWidth() &&
+				height == rendererComponent.getHeight() )
+			{
+				Point location = rendererComponent.getLocation();
+				int row = table.rowAtPoint( location );
+				int column = table.columnAtPoint( location );
+				if( row >= 0 && column >= 0 ) {
+					inPaintSelection = true;
+					if( color == table.getSelectionBackground() )
+						paintCellSelection( this, row, column, x, y, width, height );
+					else
+						paintAlternateRowBackground( this, row, column, x, y, width, height );
+					inPaintSelection = false;
+
+					return true;
+				}
+			}
+			return false;
+		}
+
+		/**
+		 * A CellRendererPane may contain multiple components, if multiple renderers
+		 * are used. Inactive renderer components have size {@code 0x0}.
+		 */
+		private Component findActiveRendererComponent() {
+			int count = rendererPane.getComponentCount();
+			for( int i = 0; i < count; i++ ) {
+				Component c = rendererPane.getComponent( i );
+				if( c.getWidth() > 0 && c.getHeight() > 0 )
+					return c;
+			}
+			return null;
+		}
+	}
+
+	//---- class OutsideAlternateRowsListener ---------------------------------
+
+	/**
+	 * Used if table auto-resize-mode is off to repaint outside alternate rows
+	 * when table width changed (column resized) or component orientation changed.
+	 */
+	private class FlatOutsideAlternateRowsListener
+		extends ComponentAdapter
+	{
+		@Override
+		public void componentHidden( ComponentEvent e ) {
+			Container viewport = SwingUtilities.getUnwrappedParent( table );
+			if( viewport instanceof JViewport )
+				HiDPIUtils.repaint( viewport );
+		}
+
+		@Override
+		public void componentMoved( ComponentEvent e ) {
+			repaintAreaBelowTable();
+		}
+
+		@Override
+		public void componentResized( ComponentEvent e ) {
+			repaintAreaBelowTable();
+		}
+
+		private void repaintAreaBelowTable() {
+			Container viewport = SwingUtilities.getUnwrappedParent( table );
+			if( viewport instanceof JViewport ) {
+				int viewportHeight = viewport.getHeight();
+				int tableHeight = table.getHeight();
+				if( tableHeight < viewportHeight )
+					HiDPIUtils.repaint( viewport, 0, tableHeight, viewport.getWidth(), viewportHeight - tableHeight );
 			}
 		}
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTextFieldUI.java

@@ -239,7 +239,7 @@ public class FlatTextFieldUI
 			case COMPONENT_ROUND_RECT:
 			case OUTLINE:
 			case TEXT_FIELD_PADDING:
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case MINIMUM_WIDTH:
@@ -250,38 +250,38 @@ public class FlatTextFieldUI
 			case STYLE_CLASS:
 				installStyle();
 				c.revalidate();
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case TEXT_FIELD_LEADING_ICON:
 				leadingIcon = (e.getNewValue() instanceof Icon) ? (Icon) e.getNewValue() : null;
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case TEXT_FIELD_TRAILING_ICON:
 				trailingIcon = (e.getNewValue() instanceof Icon) ? (Icon) e.getNewValue() : null;
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case TEXT_FIELD_LEADING_COMPONENT:
 				uninstallLeadingComponent();
 				installLeadingComponent();
 				c.revalidate();
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case TEXT_FIELD_TRAILING_COMPONENT:
 				uninstallTrailingComponent();
 				installTrailingComponent();
 				c.revalidate();
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case TEXT_FIELD_SHOW_CLEAR_BUTTON:
 				uninstallClearButton();
 				installClearButton();
 				c.revalidate();
-				c.repaint();
+				HiDPIUtils.repaint( c );
 				break;
 
 			case "enabled":
@@ -815,7 +815,7 @@ debug*/
 		if( visible != clearButton.isVisible() ) {
 			clearButton.setVisible( visible );
 			c.revalidate();
-			c.repaint();
+			HiDPIUtils.repaint( c );
 		}
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTitlePane.java

@@ -110,6 +110,7 @@ public class FlatTitlePane
 	extends JComponent
 {
 	static final String KEY_DEBUG_SHOW_RECTANGLES = "FlatLaf.debug.titlebar.showRectangles";
+	private static final boolean isWindows_10 = SystemInfo.isWindows_10_orLater && !SystemInfo.isWindows_11_orLater;
 
 	/** @since 2.5 */ protected final Font titleFont;
 	protected final Color activeBackground;
@@ -166,6 +167,16 @@ public class FlatTitlePane
 	 */
 	final JPanel mouseLayer;
 
+	/**
+	 * This panel paint a border at the top of the window in fullWindowContent mode,
+	 * if FlatLaf window decorations are enabled.
+	 * Only used on Windows 10.
+	 * <p>
+	 * This panel is not a child of the title pane.
+	 * Instead it is added by FlatRootPaneUI to the layered pane at a layer over all other layers.
+	 */
+	final JPanel windowTopBorderLayer;
+
 	public FlatTitlePane( JRootPane rootPane ) {
 		this.rootPane = rootPane;
 
@@ -207,6 +218,14 @@ public class FlatTitlePane
 		mouseLayer.addMouseListener( handler );
 		mouseLayer.addMouseMotionListener( handler );
 
+		if( isWindows_10 && FlatNativeWindowBorder.isSupported() ) {
+			windowTopBorderLayer = new JPanel();
+			windowTopBorderLayer.setVisible( false );
+			windowTopBorderLayer.setOpaque( false );
+			windowTopBorderLayer.setBorder( FlatUIUtils.nonUIResource( WindowTopBorder.getInstance() ) );
+		} else
+			windowTopBorderLayer = null;
+
 		applyComponentOrientation( rootPane.getComponentOrientation() );
 	}
 
@@ -340,6 +359,10 @@ public class FlatTitlePane
 			@Override
 			public Dimension getPreferredSize() {
 				Dimension size = super.getPreferredSize();
+				int titleBarHeight = clientPropertyInt( rootPane, TITLE_BAR_HEIGHT, -1 );
+				if( titleBarHeight >= 0 )
+					return new Dimension( size.width, UIScale.scale( titleBarHeight ) );
+
 				if( buttonMaximizedHeight > 0 && isWindowMaximized() && !hasVisibleEmbeddedMenuBar( rootPane.getJMenuBar() ) ) {
 					// make title pane height smaller when frame is maximized
 					size = new Dimension( size.width, Math.min( size.height, UIScale.scale( buttonMaximizedHeight ) ) );
@@ -376,6 +399,12 @@ public class FlatTitlePane
 				// allow the button to shrink if space is rare
 				return new Dimension( UIScale.scale( buttonMinimumWidth ), super.getMinimumSize().height );
 			}
+			@Override
+			public Dimension getMaximumSize() {
+				// allow the button to fill whole button area height
+				// see also BasicMenuUI.getMaximumSize()
+				return new Dimension( super.getMaximumSize().width, Short.MAX_VALUE );
+			}
 		};
 		button.setFocusable( false );
 		button.setContentAreaFilled( false );
@@ -726,16 +755,6 @@ public class FlatTitlePane
 		g.fillRect( 0, 0, getWidth(), getHeight() );
 	}
 
-	protected void repaintWindowBorder() {
-		int width = rootPane.getWidth();
-		int height = rootPane.getHeight();
-		Insets insets = rootPane.getInsets();
-		rootPane.repaint( 0, 0, width, insets.top ); // top
-		rootPane.repaint( 0, 0, insets.left, height ); // left
-		rootPane.repaint( 0, height - insets.bottom, width, insets.bottom ); // bottom
-		rootPane.repaint( width - insets.right, 0, insets.right, height ); // right
-	}
-
 	/**
 	 * Iconifies the window.
 	 */
@@ -919,6 +938,10 @@ public class FlatTitlePane
 		return window != null && FlatNativeWindowBorder.hasCustomDecoration( window );
 	}
 
+	boolean isWindowTopBorderNeeded() {
+		return isWindows_10 && hasNativeCustomDecoration();
+	}
+
 	// used to invoke updateNativeTitleBarHeightAndHitTestSpots() only once from latest invokeLater()
 	private int laterCounter;
 
@@ -1066,7 +1089,7 @@ public class FlatTitlePane
 	}
 
 	private boolean isTitleBarCaptionAt( Component c, int x, int y ) {
-		if( !c.isDisplayable() || !c.isVisible() || !c.contains( x, y ) || c == mouseLayer )
+		if( !c.isDisplayable() || !c.isVisible() || !contains( c, x, y ) || c == mouseLayer )
 			return true; // continue checking with next component
 
 		if( c.isEnabled() &&
@@ -1118,6 +1141,16 @@ public class FlatTitlePane
 		return true;
 	}
 
+	/**
+	 * Same as {@link Component#contains(int, int)}, but not using that method
+	 * because it may be overridden by custom components and invoke code that
+	 * tries to request AWT tree lock on 'AWT-Windows' thread.
+	 * This could freeze the application if AWT tree is already locked on 'AWT-EventQueue' thread.
+	 */
+	private boolean contains( Component c, int x, int y ) {
+		return x >= 0 && y >= 0 && x < c.getWidth() && y < c.getHeight();
+	}
+
 	private int lastCaptionHitTestX;
 	private int lastCaptionHitTestY;
 	private long lastCaptionHitTestTime;
@@ -1146,7 +1179,7 @@ public class FlatTitlePane
 			} else if( borderColor != null && (rootPane.getJMenuBar() == null || !rootPane.getJMenuBar().isVisible()) )
 				insets.bottom += UIScale.scale( 1 );
 
-			if( !SystemInfo.isWindows_11_orLater && hasNativeCustomDecoration() && !isWindowMaximized() )
+			if( isWindowTopBorderNeeded() && !isWindowMaximized() )
 				insets = FlatUIUtils.addInsets( insets, WindowTopBorder.getInstance().getBorderInsets() );
 
 			return insets;
@@ -1165,7 +1198,7 @@ public class FlatTitlePane
 				FlatUIUtils.paintFilledRectangle( g, borderColor, x, y + height - lineHeight, width, lineHeight );
 			}
 
-			if( !SystemInfo.isWindows_11_orLater && hasNativeCustomDecoration() && !isWindowMaximized() )
+			if( isWindowTopBorderNeeded() && !isWindowMaximized() && !isFullWindowContent() )
 				WindowTopBorder.getInstance().paintBorder( c, g, x, y, width, height );
 		}
 
@@ -1329,10 +1362,7 @@ public class FlatTitlePane
 			activeChanged( true );
 			updateNativeTitleBarHeightAndHitTestSpots();
 
-			if( !SystemInfo.isWindows_11_orLater && hasNativeCustomDecoration() )
-				WindowTopBorder.getInstance().repaintBorder( FlatTitlePane.this );
-
-			repaintWindowBorder();
+			repaintBorder();
 		}
 
 		@Override
@@ -1340,10 +1370,22 @@ public class FlatTitlePane
 			activeChanged( false );
 			updateNativeTitleBarHeightAndHitTestSpots();
 
-			if( !SystemInfo.isWindows_11_orLater && hasNativeCustomDecoration() )
+			repaintBorder();
+		}
+
+		private void repaintBorder() {
+			// Windows 10 top border
+			if( windowTopBorderLayer != null && windowTopBorderLayer.isShowing())
+				WindowTopBorder.getInstance().repaintBorder( windowTopBorderLayer );
+			else if( isWindowTopBorderNeeded() && !isWindowMaximized() && !isFullWindowContent() )
 				WindowTopBorder.getInstance().repaintBorder( FlatTitlePane.this );
 
-			repaintWindowBorder();
+			// Window border used for non-native window decorations
+			if( rootPane.getBorder() instanceof FlatRootPaneUI.FlatWindowBorder ) {
+				// not repainting four areas on the four sides because RepaintManager
+				// unions dirty regions, which also results in repaint of whole rootpane
+				rootPane.repaint();
+			}
 		}
 
 		@Override

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatToggleButtonUI.java

@@ -26,6 +26,7 @@ import javax.swing.*;
 import javax.swing.plaf.ComponentUI;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.UnknownStyleException;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.UIScale;
 
 /**
@@ -159,14 +160,14 @@ public class FlatToggleButtonUI
 					b.revalidate();
 				}
 
-				b.repaint();
+				HiDPIUtils.repaint( b );
 				break;
 
 			case TAB_BUTTON_UNDERLINE_PLACEMENT:
 			case TAB_BUTTON_UNDERLINE_HEIGHT:
 			case TAB_BUTTON_UNDERLINE_COLOR:
 			case TAB_BUTTON_SELECTED_BACKGROUND:
-				b.repaint();
+				HiDPIUtils.repaint( b );
 				break;
 		}
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatToolBarSeparatorUI.java

@@ -36,6 +36,7 @@ import javax.swing.plaf.basic.BasicToolBarSeparatorUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 
 /**
@@ -131,7 +132,7 @@ public class FlatToolBarSeparatorUI
 				} else
 					installStyle( s );
 				s.revalidate();
-				s.repaint();
+				HiDPIUtils.repaint( s );
 				break;
 		}
 	}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatToolBarUI.java

@@ -47,6 +47,7 @@ import javax.swing.plaf.basic.BasicToolBarUI;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -443,7 +444,7 @@ public class FlatToolBarUI
 
 		// repaint button group
 		if( gr != null )
-			toolBar.repaint( gr );
+			HiDPIUtils.repaint(toolBar, gr );
 	}
 
 	private ButtonGroup getButtonGroup( AbstractButton b ) {
@@ -530,8 +531,11 @@ public class FlatToolBarUI
 
 		private Component getRecentComponent( Container aContainer, boolean first ) {
 			// if moving focus into the toolbar, focus recently focused toolbar button
-			if( focusedCompIndex >= 0 && focusedCompIndex < toolBar.getComponentCount() )
-				return toolBar.getComponent( focusedCompIndex );
+			if( focusedCompIndex >= 0 && focusedCompIndex < toolBar.getComponentCount() ) {
+				Component c = toolBar.getComponent( focusedCompIndex );
+				if( accept( c ) )
+					return c;
+			}
 
 			return first
 				? super.getFirstComponent( aContainer )

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatToolTipUI.java

@@ -61,7 +61,7 @@ public class FlatToolTipUI
 		super.installUI( c );
 
 		// update HTML renderer if necessary
-		FlatLabelUI.updateHTMLRenderer( c, ((JToolTip)c).getTipText(), false );
+		FlatHTML.updateRendererCSSFontBaseSize( c );
 	}
 
 	@Override
@@ -81,11 +81,7 @@ public class FlatToolTipUI
 	/** @since 2.0.1 */
 	@Override
 	public void propertyChange( PropertyChangeEvent e ) {
-		String name = e.getPropertyName();
-		if( name == "tiptext" || name == "font" || name == "foreground" ) {
-			JToolTip toolTip = (JToolTip) e.getSource();
-			FlatLabelUI.updateHTMLRenderer( toolTip, toolTip.getTipText(), false );
-		}
+		FlatHTML.propertyChange( e );
 	}
 
 	@Override

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTreeUI.java

@@ -47,6 +47,7 @@ import javax.swing.tree.DefaultTreeCellRenderer;
 import javax.swing.tree.TreePath;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
+import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -310,7 +311,7 @@ public class FlatTreeUI
 				switch( e.getPropertyName() ) {
 					case TREE_WIDE_SELECTION:
 					case TREE_PAINT_SELECTION:
-						tree.repaint();
+						HiDPIUtils.repaint( tree );
 						break;
 
 					case "dropLocation":
@@ -325,7 +326,7 @@ public class FlatTreeUI
 					case STYLE_CLASS:
 						installStyle();
 						tree.revalidate();
-						tree.repaint();
+						HiDPIUtils.repaint( tree );
 						break;
 
 					case "enabled":
@@ -353,7 +354,7 @@ public class FlatTreeUI
 
 		Rectangle r = tree.getPathBounds( loc.getPath() );
 		if( r != null )
-			tree.repaint( 0, r.y, tree.getWidth(), r.height );
+			HiDPIUtils.repaint( tree, 0, r.y, tree.getWidth(), r.height );
 	}
 
 	@Override
@@ -370,14 +371,14 @@ public class FlatTreeUI
 			{
 				if( changedPaths.length > 4 ) {
 					// same is done in BasicTreeUI.Handler.valueChanged()
-					tree.repaint();
+					HiDPIUtils.repaint( tree );
 				} else {
 					int arc = (int) Math.ceil( UIScale.scale( selectionArc / 2f ) );
 
 					for( TreePath path : changedPaths ) {
 						Rectangle r = getPathBounds( tree, path );
 						if( r != null )
-							tree.repaint( r.x, r.y - arc, r.width, r.height + (arc * 2) );
+							HiDPIUtils.repaint( tree, r.x, r.y - arc, r.width, r.height + (arc * 2) );
 					}
 				}
 			}

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatUIUtils.java

@@ -124,6 +124,11 @@ public class FlatUIUtils
 		dest.right = src.right;
 	}
 
+	/** @since 3.5 */
+	public static boolean isInsetsEmpty( Insets insets ) {
+		return insets.top == 0 && insets.left == 0 && insets.bottom == 0 && insets.right == 0;
+	}
+
 	public static Color getUIColor( String key, int defaultColorRGB ) {
 		Color color = UIManager.getColor( key );
 		return (color != null) ? color : new Color( defaultColorRGB );
@@ -601,28 +606,55 @@ public class FlatUIUtils
 	public static void paintOutlinedComponent( Graphics2D g, int x, int y, int width, int height,
 		float focusWidth, float focusWidthFraction, float focusInnerWidth, float borderWidth, float arc,
 		Paint focusColor, Paint borderColor, Paint background )
+	{
+		paintOutlinedComponent( g, x, y, width, height, focusWidth, focusWidthFraction, focusInnerWidth,
+			borderWidth, arc, focusColor, borderColor, background, false );
+	}
+
+	static void paintOutlinedComponent( Graphics2D g, int x, int y, int width, int height,
+		float focusWidth, float focusWidthFraction, float focusInnerWidth, float borderWidth, float arc,
+		Paint focusColor, Paint borderColor, Paint background, boolean scrollPane )
 	{
 		double systemScaleFactor = UIScale.getSystemScaleFactor( g );
-		if( systemScaleFactor != 1 && systemScaleFactor != 2 ) {
+		if( (int) systemScaleFactor != systemScaleFactor ) {
 			// paint at scale 1x to avoid clipping on right and bottom edges at 125%, 150% or 175%
 			HiDPIUtils.paintAtScale1x( g, x, y, width, height,
 				(g2d, x2, y2, width2, height2, scaleFactor) -> {
 					paintOutlinedComponentImpl( g2d, x2, y2, width2, height2,
 						(float) (focusWidth * scaleFactor), focusWidthFraction, (float) (focusInnerWidth * scaleFactor),
 						(float) (borderWidth * scaleFactor), (float) (arc * scaleFactor),
-						focusColor, borderColor, background );
+						focusColor, borderColor, background, scrollPane, scaleFactor );
 				} );
 			return;
 		}
 
 		paintOutlinedComponentImpl( g, x, y, width, height, focusWidth, focusWidthFraction, focusInnerWidth,
-			borderWidth, arc, focusColor, borderColor, background );
+			borderWidth, arc, focusColor, borderColor, background, scrollPane, systemScaleFactor );
 	}
 
+	@SuppressWarnings( "SelfAssignment" ) // Error Prone
 	private static void paintOutlinedComponentImpl( Graphics2D g, int x, int y, int width, int height,
 		float focusWidth, float focusWidthFraction, float focusInnerWidth, float borderWidth, float arc,
-		Paint focusColor, Paint borderColor, Paint background )
+		Paint focusColor, Paint borderColor, Paint background, boolean scrollPane, double scaleFactor )
 	{
+		// Special handling for scrollpane and fractional scale factors (e.g. 1.25 - 1.75),
+		// where Swing scales one "logical" pixel (border insets) to either one or two physical pixels.
+		// Antialiasing is used to paint the border, which usually needs two physical pixels
+		// at small scale factors. 1px for the solid border and another 1px for antialiasing.
+		// But scrollpane view is painted over the border, which results in a painted border
+		// that is 1px thick at some sides and 2px thick at other sides.
+		if( scrollPane && scaleFactor != (int) scaleFactor ) {
+			if( focusWidth > 0 ) {
+				// reduce outer border thickness (focusWidth) so that inner side of
+				// component border (focusWidth + borderWidth) is at a full pixel
+				int totalWidth = (int) (focusWidth + borderWidth);
+				focusWidth = totalWidth - borderWidth;
+			} else {// if( scaleFactor > 1 && scaleFactor < 2 ) {
+				// reduce component border thickness (borderWidth) to full pixels
+				borderWidth = (int) borderWidth;
+			}
+		}
+
 		// outside bounds of the border and the background
 		float x1 = x + focusWidth;
 		float y1 = y + focusWidth;
@@ -780,7 +812,7 @@ public class FlatUIUtils
 
 		if( arcTopLeft > 0 || arcTopRight > 0 || arcBottomLeft > 0 || arcBottomRight > 0 ) {
 			double systemScaleFactor = UIScale.getSystemScaleFactor( g );
-			if( systemScaleFactor != 1 && systemScaleFactor != 2 ) {
+			if( systemScaleFactor != (int) systemScaleFactor ) {
 				// paint at scale 1x to avoid clipping on right and bottom edges at 125%, 150% or 175%
 				HiDPIUtils.paintAtScale1x( g, x, y, width, height,
 					(g2d, x2, y2, width2, height2, scaleFactor) -> {
@@ -1315,13 +1347,13 @@ debug*/
 		@Override
 		public void focusGained( FocusEvent e ) {
 			if( repaintCondition == null || repaintCondition.test( repaintComponent ) )
-				repaintComponent.repaint();
+				HiDPIUtils.repaint( repaintComponent );
 		}
 
 		@Override
 		public void focusLost( FocusEvent e ) {
 			if( repaintCondition == null || repaintCondition.test( repaintComponent ) )
-				repaintComponent.repaint();
+				HiDPIUtils.repaint( repaintComponent );
 		}
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowsNativeWindowBorder.java

@@ -89,7 +89,7 @@ class FlatWindowsNativeWindowBorder
 			return null;
 
 		// check whether native library was successfully loaded
-		if( !FlatNativeLibrary.isLoaded() )
+		if( !FlatNativeWindowsLibrary.isLoaded() )
 			return null;
 
 		// create new instance

flatlaf-core/src/main/java/com/formdev/flatlaf/util/HiDPIUtils.java

@@ -16,14 +16,17 @@
 
 package com.formdev.flatlaf.util;
 
+import java.awt.Component;
 import java.awt.Font;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
+import java.awt.Rectangle;
 import java.awt.font.GlyphVector;
 import java.awt.geom.AffineTransform;
 import java.awt.geom.Rectangle2D;
 import java.text.AttributedCharacterIterator;
 import javax.swing.JComponent;
+import javax.swing.RepaintManager;
 import com.formdev.flatlaf.FlatSystemProperties;
 
 /**
@@ -322,4 +325,243 @@ public class HiDPIUtils
 			}
 		};
 	}
+
+	/**
+	 * Repaints the given component.
+	 * <p>
+	 * See {@link #repaint(Component, int, int, int, int)} for more details.
+	 *
+	 * @since 3.5
+	 */
+	public static void repaint( Component c ) {
+		repaint( c, 0, 0, c.getWidth(), c.getHeight() );
+	}
+
+	/**
+	 * Repaints the given component area.
+	 * <p>
+	 * See {@link #repaint(Component, int, int, int, int)} for more details.
+	 *
+	 * @since 3.5
+	 */
+	public static void repaint( Component c, Rectangle r ) {
+		repaint( c, r.x, r.y, r.width, r.height );
+	}
+
+	/**
+	 * Repaints the given component area.
+	 * <p>
+	 * Invokes {@link Component#repaint(int, int, int, int)} on the given component,
+	 * <p>
+	 * Use this method, instead of {@code Component.repaint(...)},
+	 * to fix a problem in Swing when using scale factors that end on .25 or .75
+	 * (e.g. 1.25, 1.75, 2.25, etc) and repainting single components, which may not
+	 * repaint right and/or bottom 1px edge of component.
+	 * <p>
+	 * The problem may occur under following conditions:
+	 * <ul>
+	 *   <li>using Java 9 or later
+	 *   <li>system scale factor is 125%, 175%, 225%, ...
+	 *       (Windows only; Java on macOS and Linux does not support fractional scale factors)
+	 *   <li>repaint whole component or right/bottom area of component
+	 *   <li>component is opaque; or component is contained in a opaque container
+	 *       that has same right/bottom bounds as component
+	 *   <li>component has bounds that Java/Swing scales different when repainting components
+	 * </ul>
+	 *
+	 * @since 3.5
+	 */
+	public static void repaint( Component c, int x, int y, int width, int height ) {
+		// repaint given component area
+		//   Always invoke repaint() on given component, even if also invoked (below)
+		//   on one of its ancestors, for the case that component overrides that method.
+		//   Also RepaintManager "merges" the two repaints into one.
+		c.repaint( x, y, width, height );
+
+		if( RepaintManager.currentManager( c ) instanceof HiDPIRepaintManager )
+			return;
+
+		// if necessary, also repaint given area in first ancestor that is larger than component
+		// to avoid clipping issue (see needsSpecialRepaint())
+		if( needsSpecialRepaint( c, x, y, width, height ) ) {
+			int x2 = x + c.getX();
+			int y2 = y + c.getY();
+			for( Component p = c.getParent(); p != null; p = p.getParent() ) {
+				x2 += p.getX();
+				y2 += p.getY();
+				if( x2 + width < p.getWidth() && y2 + height < p.getHeight() ) {
+					p.repaint( x2, y2, width, height );
+					break;
+				}
+			}
+		}
+	}
+
+	/**
+	 * There is a problem in Swing, when using scale factors that end on .25 or .75
+	 * (e.g. 1.25, 1.75, 2.25, etc) and repainting single components, which may not
+	 * repaint right and/or bottom 1px edge of component.
+	 * <p>
+	 * The component is first painted to an in-memory image,
+	 * and then that image is copied to the screen.
+	 * See {@code javax.swing.RepaintManager.PaintManager#paintDoubleBufferedFPScales()}.
+	 * <p>
+	 * There are two clipping rectangles involved when copying the image to the screen:
+	 * {@code sun.java2d.SunGraphics2D#devClip} and
+	 * {@code sun.java2d.SunGraphics2D#usrClip}.
+	 * <p>
+	 * {@code devClip} is the device clipping in physical pixels.
+	 * It gets the bounds of the painting component, which is either the passed component,
+	 * or if it is non-opaque, then the first opaque ancestor of the passed component.
+	 * It is calculated in {@code sun.java2d.SunGraphics2D#constrain()} while
+	 * getting a graphics context via {@link JComponent#getGraphics()}.
+	 * <p>
+	 * {@code usrClip} is the user clipping, which is set via {@link Graphics} clipping methods.
+	 * This is done in {@code javax.swing.RepaintManager.PaintManager#paintDoubleBufferedFPScales()}.
+	 * <p>
+	 * The intersection of {@code devClip} and {@code usrClip}
+	 * (computed in {@code sun.java2d.SunGraphics2D#validateCompClip()})
+	 * is used to copy the image to the screen.
+	 * <p>
+	 * Unfortunately different scaling/rounding strategies are used to calculate
+	 * the two clipping rectangles, which is the reason of the issue.
+	 * <p>
+	 * {@code devClip} (see {@code sun.java2d.SunGraphics2D#constrain()}):
+	 * <pre>{@code
+	 * int devX = (int) (x * scale);
+	 * int devWidth = Math.round( width * scale )
+	 * }</pre>
+	 * {@code usrClip} (see {@code javax.swing.RepaintManager.PaintManager#paintDoubleBufferedFPScales()}):
+	 * <pre>{@code
+	 * int usrX = (int) Math.ceil( (x * scale) - 0.5 );
+	 * int usrWidth = ((int) Math.ceil( ((x + width) * scale) - 0.5 )) - usrX;
+	 * }</pre>
+	 * X/Y coordinates are always rounded down for {@code devClip}, but rounded up for {@code usrClip}.
+	 * Width/height calculation is also different.
+	 */
+	private static boolean needsSpecialRepaint( Component c, int x, int y, int width, int height ) {
+		// no special repaint necessary for Java 8 or for macOS and Linux
+		// (Java on those platforms does not support fractional scale factors)
+		if( !SystemInfo.isJava_9_orLater || !SystemInfo.isWindows )
+			return false;
+
+		// check whether repaint area is empty or no component given
+		// (same checks as in javax.swing.RepaintManager.addDirtyRegion0())
+		if( width <= 0 || height <= 0 || c == null )
+			return false;
+
+		// check whether component has zero size
+		// (same checks as in javax.swing.RepaintManager.addDirtyRegion0())
+		int compWidth = c.getWidth();
+		int compHeight = c.getHeight();
+		if( compWidth <= 0 || compHeight <= 0 )
+			return false;
+
+		// check whether repaint area does span to right or bottom component edges
+		// (in this case, {@code devClip} is always larger than {@code usrClip})
+		if( x + width < compWidth && y + height < compHeight )
+			return false;
+
+		// if component is not opaque, Swing uses the first opaque ancestor for painting
+		if( !c.isOpaque() ) {
+			int x2 = x;
+			int y2 = y;
+			for( Component p = c.getParent(); p != null; p = p.getParent() ) {
+				x2 += p.getX();
+				y2 += p.getY();
+				if( p.isOpaque() ) {
+					// check whether repaint area does span to right or bottom edges
+					// of the opaque ancestor component
+					// (in this case, {@code devClip} is always larger than {@code usrClip})
+					if( x2 + width < p.getWidth() && y2 + height < p.getHeight() )
+						return false;
+					break;
+				}
+			}
+		}
+
+		// check whether Special repaint is necessary for current scale factor
+		// (doing this check late because it temporary allocates some memory)
+		double scaleFactor = UIScale.getSystemScaleFactor( c.getGraphicsConfiguration() );
+		double fraction = scaleFactor - (int) scaleFactor;
+		if( fraction == 0 || fraction == 0.5 )
+			return false;
+
+		return true;
+	}
+
+	/**
+	 * Installs a {@link HiDPIRepaintManager} on Windows when running in Java 9+,
+	 * but only if default repaint manager is currently installed.
+	 * <p>
+	 * Invoke once on application startup.
+	 * Compatible with all/other LaFs.
+	 *
+	 * @since 3.5
+	 */
+	public static void installHiDPIRepaintManager() {
+		if( !SystemInfo.isJava_9_orLater || !SystemInfo.isWindows )
+			return;
+
+		RepaintManager manager = RepaintManager.currentManager( (Component) null );
+		if( manager.getClass() == RepaintManager.class )
+			RepaintManager.setCurrentManager( new HiDPIRepaintManager() );
+	}
+
+	/**
+	 * Similar to {@link #repaint(Component, int, int, int, int)},
+	 * but invokes callback instead of invoking {@link Component#repaint(int, int, int, int)}.
+	 * <p>
+	 * For use in custom repaint managers.
+	 *
+	 * @since 3.5
+	 */
+	public static void addDirtyRegion( JComponent c, int x, int y, int width, int height, DirtyRegionCallback callback ) {
+		if( needsSpecialRepaint( c, x, y, width, height ) ) {
+			int x2 = x + c.getX();
+			int y2 = y + c.getY();
+			for( Component p = c.getParent(); p != null; p = p.getParent() ) {
+				if( x2 + width < p.getWidth() && y2 + height < p.getHeight() && p instanceof JComponent ) {
+					callback.addDirtyRegion( (JComponent) p, x2, y2, width, height );
+					return;
+				}
+				x2 += p.getX();
+				y2 += p.getY();
+			}
+		}
+
+		callback.addDirtyRegion( c, x, y, width, height );
+	}
+
+	//---- interface DirtyRegionCallback --------------------------------------
+
+	/**
+	 * For {@link HiDPIUtils#addDirtyRegion(JComponent, int, int, int, int, DirtyRegionCallback)}.
+	 *
+	 * @since 3.5
+	 */
+	public interface DirtyRegionCallback {
+		void addDirtyRegion( JComponent c, int x, int y, int w, int h );
+	}
+
+	//---- class HiDPIRepaintManager ------------------------------------------
+
+	/**
+	 * A repaint manager that fixes a problem in Swing when repainting components
+	 * at some scale factors (e.g. 125%, 175%, etc) on Windows.
+	 * <p>
+	 * Use {@link HiDPIUtils#installHiDPIRepaintManager()} to install it.
+	 * <p>
+	 * See {@link HiDPIUtils#repaint(Component, int, int, int, int)} for details.
+	 *
+	 * @since 3.5
+	 */
+	public static class HiDPIRepaintManager
+		extends RepaintManager
+	{
+		@Override
+		public void addDirtyRegion( JComponent c, int x, int y, int w, int h ) {
+			HiDPIUtils.addDirtyRegion( c, x, y, w, h, super::addDirtyRegion );
+		}
+	}
 }

flatlaf-core/src/test/java/com/formdev/flatlaf/TestUIDefaultsLoader.java

@@ -84,10 +84,12 @@ public class TestUIDefaultsLoader
 	void parseBorders() {
 		Insets insets = new Insets( 1,2,3,4 );
 		assertBorderEquals( new FlatEmptyBorder( insets ), "1,2,3,4" );
+		assertBorderEquals( new FlatEmptyBorder( insets ), "1,2,3,4,,," );
 		assertBorderEquals( new FlatLineBorder( insets, Color.red ), "1,2,3,4,#f00" );
-		assertBorderEquals( new FlatLineBorder( insets, Color.red, 2.5f, 0 ), "1,2,3,4,#f00,2.5" );
+		assertBorderEquals( new FlatLineBorder( insets, Color.red, 2.5f, -1 ), "1,2,3,4,#f00,2.5" );
 		assertBorderEquals( new FlatLineBorder( insets, Color.red, 2.5f, 6 ), "1,2,3,4,#f00,2.5,6" );
 		assertBorderEquals( new FlatLineBorder( insets, Color.red, 1, 6 ), "1,2,3,4,#f00,,6" );
+		assertBorderEquals( new FlatLineBorder( insets, null, 1, 6 ), "1,2,3,4,,,6" );
 	}
 
 	private void assertBorderEquals( Border expected, String actualStyle ) {

flatlaf-core/src/test/java/com/formdev/flatlaf/ui/TestFlatStyleableInfo.java

@@ -253,7 +253,8 @@ public class TestFlatStyleableInfo
 		FlatLabelUI ui = (FlatLabelUI) c.getUI();
 
 		Map<String, Class<?>> expected = expectedMap(
-			"disabledForeground", Color.class
+			"disabledForeground", Color.class,
+			"arc", int.class
 		);
 
 		assertMapEquals( expected, ui.getStyleableInfos( c ) );
@@ -799,6 +800,8 @@ public class TestFlatStyleableInfo
 			"selectionForeground", Color.class,
 			"selectionInactiveBackground", Color.class,
 			"selectionInactiveForeground", Color.class,
+			"selectionInsets", Insets.class,
+			"selectionArc", int.class,
 
 			// FlatTableCellBorder
 			"cellMargins", Insets.class,
@@ -993,12 +996,20 @@ public class TestFlatStyleableInfo
 			"disabledBorderColor", Color.class,
 			"focusedBorderColor", Color.class,
 			"hoverBorderColor", Color.class,
+			"pressedBorderColor", Color.class,
+
+			"selectedBorderColor", Color.class,
+			"disabledSelectedBorderColor", Color.class,
+			"focusedSelectedBorderColor", Color.class,
+			"hoverSelectedBorderColor", Color.class,
+			"pressedSelectedBorderColor", Color.class,
 
 			"default.borderWidth", float.class,
 			"default.borderColor", Color.class,
 			"default.focusedBorderColor", Color.class,
 			"default.focusColor", Color.class,
 			"default.hoverBorderColor", Color.class,
+			"default.pressedBorderColor", Color.class,
 
 			"toolbar.focusWidth", float.class,
 			"toolbar.focusColor", Color.class,

flatlaf-core/src/test/java/com/formdev/flatlaf/ui/TestFlatStyleableValue.java

@@ -305,6 +305,9 @@ public class TestFlatStyleableValue
 		testColor( c, ui, "buttonPressedArrowColor", 0x123456 );
 
 		testColor( c, ui, "popupBackground", 0x123456 );
+		testInsets( c, ui, "popupInsets", 1,2,3,4 );
+		testInsets( c, ui, "selectionInsets", 1,2,3,4 );
+		testInteger( c, ui, "selectionArc", 123 );
 
 		// border
 		flatRoundBorder( c, ui );
@@ -355,6 +358,7 @@ public class TestFlatStyleableValue
 		FlatLabelUI ui = (FlatLabelUI) c.getUI();
 
 		testColor( c, ui, "disabledForeground", 0x123456 );
+		testInteger( c, ui, "arc", 123 );
 	}
 
 	@Test
@@ -366,6 +370,8 @@ public class TestFlatStyleableValue
 		testColor( c, ui, "selectionForeground", 0x123456 );
 		testColor( c, ui, "selectionInactiveBackground", 0x123456 );
 		testColor( c, ui, "selectionInactiveForeground", 0x123456 );
+		testInsets( c, ui, "selectionInsets", 1,2,3,4 );
+		testInteger( c, ui, "selectionArc", 123 );
 
 		// FlatListCellBorder
 		testInsets( c, ui, "cellMargins", 1,2,3,4 );
@@ -801,6 +807,8 @@ public class TestFlatStyleableValue
 		testColor( c, ui, "selectionForeground", 0x123456 );
 		testColor( c, ui, "selectionInactiveBackground", 0x123456 );
 		testColor( c, ui, "selectionInactiveForeground", 0x901324 );
+		testInsets( c, ui, "selectionInsets", 1,2,3,4 );
+		testInteger( c, ui, "selectionArc", 123 );
 
 		// FlatTableCellBorder
 		testInsets( c, ui, "cellMargins", 1,2,3,4 );
@@ -930,6 +938,8 @@ public class TestFlatStyleableValue
 		testColor( c, ui, "selectionInactiveBackground", 0x123456 );
 		testColor( c, ui, "selectionInactiveForeground", 0x123456 );
 		testColor( c, ui, "selectionBorderColor", 0x123456 );
+		testInsets( c, ui, "selectionInsets", 1,2,3,4 );
+		testInteger( c, ui, "selectionArc", 123 );
 		testBoolean( c, ui, "wideSelection", true );
 		testBoolean( c, ui, "showCellFocusIndicator", true );
 
@@ -955,12 +965,20 @@ public class TestFlatStyleableValue
 		testColor( c, ui, "disabledBorderColor", 0x123456 );
 		testColor( c, ui, "focusedBorderColor", 0x123456 );
 		testColor( c, ui, "hoverBorderColor", 0x123456 );
+		testColor( c, ui, "pressedBorderColor", 0x123456 );
+
+		testColor( c, ui, "selectedBorderColor", 0x123456 );
+		testColor( c, ui, "disabledSelectedBorderColor", 0x123456 );
+		testColor( c, ui, "focusedSelectedBorderColor", 0x123456 );
+		testColor( c, ui, "hoverSelectedBorderColor", 0x123456 );
+		testColor( c, ui, "pressedSelectedBorderColor", 0x123456 );
 
 		testFloat( c, ui, "default.borderWidth", 1.23f );
 		testColor( c, ui, "default.borderColor", 0x123456 );
 		testColor( c, ui, "default.focusedBorderColor", 0x123456 );
 		testColor( c, ui, "default.focusColor", 0x123456 );
 		testColor( c, ui, "default.hoverBorderColor", 0x123456 );
+		testColor( c, ui, "default.pressedBorderColor", 0x123456 );
 
 		testFloat( c, ui, "toolbar.focusWidth", 1.23f );
 		testColor( c, ui, "toolbar.focusColor", 0x123456 );
@@ -1025,12 +1043,20 @@ public class TestFlatStyleableValue
 		testValue( border, "disabledBorderColor", Color.WHITE );
 		testValue( border, "focusedBorderColor", Color.WHITE );
 		testValue( border, "hoverBorderColor", Color.WHITE );
+		testValue( border, "pressedBorderColor", Color.WHITE );
+
+		testValue( border, "selectedBorderColor", Color.WHITE );
+		testValue( border, "disabledSelectedBorderColor", Color.WHITE );
+		testValue( border, "focusedSelectedBorderColor", Color.WHITE );
+		testValue( border, "hoverSelectedBorderColor", Color.WHITE );
+		testValue( border, "pressedSelectedBorderColor", Color.WHITE );
 
 		testValue( border, "default.borderWidth", 2f );
 		testValue( border, "default.borderColor", Color.WHITE );
 		testValue( border, "default.focusedBorderColor", Color.WHITE );
 		testValue( border, "default.focusColor", Color.WHITE );
 		testValue( border, "default.hoverBorderColor", Color.WHITE );
+		testValue( border, "default.pressedBorderColor", Color.WHITE );
 
 		testValue( border, "toolbar.focusWidth", 1.5f );
 		testValue( border, "toolbar.focusColor", Color.WHITE );

flatlaf-core/src/test/java/com/formdev/flatlaf/ui/TestFlatStyling.java

@@ -412,6 +412,7 @@ public class TestFlatStyling
 		FlatLabelUI ui = (FlatLabelUI) c.getUI();
 
 		ui.applyStyle( c, "disabledForeground: #fff" );
+		ui.applyStyle( c, "arc: 8" );
 
 		// JComponent properties
 		ui.applyStyle( c, "background: #fff" );
@@ -986,6 +987,8 @@ public class TestFlatStyling
 		ui.applyStyle( "selectionForeground: #fff" );
 		ui.applyStyle( "selectionInactiveBackground: #fff" );
 		ui.applyStyle( "selectionInactiveForeground: #fff" );
+		ui.applyStyle( "selectionInsets: 1,2,3,4" );
+		ui.applyStyle( "selectionArc: 8" );
 
 		// FlatTableCellBorder
 		ui.applyStyle( "cellMargins: 1,2,3,4" );
@@ -1294,12 +1297,20 @@ public class TestFlatStyling
 		border.applyStyleProperty( "disabledBorderColor", Color.WHITE );
 		border.applyStyleProperty( "focusedBorderColor", Color.WHITE );
 		border.applyStyleProperty( "hoverBorderColor", Color.WHITE );
+		border.applyStyleProperty( "pressedBorderColor", Color.WHITE );
+
+		border.applyStyleProperty( "selectedBorderColor", Color.WHITE );
+		border.applyStyleProperty( "disabledSelectedBorderColor", Color.WHITE );
+		border.applyStyleProperty( "focusedSelectedBorderColor", Color.WHITE );
+		border.applyStyleProperty( "hoverSelectedBorderColor", Color.WHITE );
+		border.applyStyleProperty( "pressedSelectedBorderColor", Color.WHITE );
 
 		border.applyStyleProperty( "default.borderWidth", 2 );
 		border.applyStyleProperty( "default.borderColor", Color.WHITE );
 		border.applyStyleProperty( "default.focusedBorderColor", Color.WHITE );
 		border.applyStyleProperty( "default.focusColor", Color.WHITE );
 		border.applyStyleProperty( "default.hoverBorderColor", Color.WHITE );
+		border.applyStyleProperty( "default.pressedBorderColor", Color.WHITE );
 
 		border.applyStyleProperty( "toolbar.focusWidth", 1.5f );
 		border.applyStyleProperty( "toolbar.focusColor", Color.WHITE );

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/ControlBar.java

@@ -140,8 +140,8 @@ class ControlBar
 			registerSwitchToLookAndFeel( KeyEvent.VK_F9, "com.apple.laf.AquaLookAndFeel" );
 		else if( SystemInfo.isLinux )
 			registerSwitchToLookAndFeel( KeyEvent.VK_F9, "com.sun.java.swing.plaf.gtk.GTKLookAndFeel" );
-		registerSwitchToLookAndFeel( KeyEvent.VK_F12, MetalLookAndFeel.class.getName() );
 		registerSwitchToLookAndFeel( KeyEvent.VK_F11, NimbusLookAndFeel.class.getName() );
+		registerSwitchToLookAndFeel( KeyEvent.VK_F12, MetalLookAndFeel.class.getName() );
 
 		// register Alt+UP and Alt+DOWN to switch to previous/next theme
 		((JComponent)frame.getContentPane()).registerKeyboardAction(
@@ -153,6 +153,9 @@ class ControlBar
 			KeyStroke.getKeyStroke( KeyEvent.VK_DOWN, KeyEvent.ALT_DOWN_MASK ),
 			JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT );
 
+		// register Alt+Shift+F1, F2, ... keys to change system scale factor
+		DemoPrefs.registerSystemScaleFactors( frame );
+
 		// register ESC key to close frame
 		((JComponent)frame.getContentPane()).registerKeyboardAction(
 			e -> {

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DataComponentsPanel.java

@@ -25,6 +25,8 @@ import javax.swing.*;
 import javax.swing.table.*;
 import javax.swing.tree.*;
 import com.formdev.flatlaf.FlatClientProperties;
+import com.formdev.flatlaf.FlatLaf;
+import com.formdev.flatlaf.util.ColorFunctions;
 import net.miginfocom.swing.*;
 
 /**
@@ -93,10 +95,12 @@ class DataComponentsPanel
 
 	private void rowSelectionChanged() {
 		table1.setRowSelectionAllowed( rowSelectionCheckBox.isSelected() );
+		roundedSelectionChanged();
 	}
 
 	private void columnSelectionChanged() {
 		table1.setColumnSelectionAllowed( columnSelectionCheckBox.isSelected() );
+		roundedSelectionChanged();
 	}
 
 	private void showHorizontalLinesChanged() {
@@ -127,6 +131,28 @@ class DataComponentsPanel
 		intercellSpacingCheckBox.setSelected( table1.getRowMargin() != 0 );
 	}
 
+	private void roundedSelectionChanged() {
+		String style = null;
+		if( roundedSelectionCheckBox.isSelected() ) {
+			style = rowSelectionCheckBox.isSelected()
+				? "selectionArc: 6; selectionInsets: 0,1,0,1"
+				: "selectionArc: 6";
+		}
+		table1.putClientProperty( FlatClientProperties.STYLE, style );
+	}
+
+	private void alternatingRowsChanged() {
+		Color alternateRowColor = null;
+		if( alternatingRowsCheckBox.isSelected() ) {
+			Color background = table1.getBackground();
+			alternateRowColor = FlatLaf.isLafDark()
+				? ColorFunctions.lighten( background, 0.05f )
+				: ColorFunctions.darken( background, 0.05f );
+		}
+		UIManager.put( "Table.alternateRowColor", alternateRowColor );
+		table1.repaint();
+	}
+
 	@SuppressWarnings( { "unchecked", "rawtypes" } )
 	private void initComponents() {
 		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
@@ -151,12 +177,14 @@ class DataComponentsPanel
 		JScrollPane scrollPane5 = new JScrollPane();
 		table1 = new JTable();
 		JPanel tableOptionsPanel = new JPanel();
+		roundedSelectionCheckBox = new JCheckBox();
 		showHorizontalLinesCheckBox = new JCheckBox();
 		showVerticalLinesCheckBox = new JCheckBox();
 		intercellSpacingCheckBox = new JCheckBox();
 		redGridColorCheckBox = new JCheckBox();
 		rowSelectionCheckBox = new JCheckBox();
 		columnSelectionCheckBox = new JCheckBox();
+		alternatingRowsCheckBox = new JCheckBox();
 		dndCheckBox = new JCheckBox();
 		JPopupMenu popupMenu2 = new JPopupMenu();
 		JMenuItem menuItem3 = new JMenuItem();
@@ -403,44 +431,56 @@ class DataComponentsPanel
 				"[]0" +
 				"[]0" +
 				"[]0" +
+				"[]0" +
+				"[]0" +
 				"[]0"));
 
+			//---- roundedSelectionCheckBox ----
+			roundedSelectionCheckBox.setText("rounded selection");
+			roundedSelectionCheckBox.addActionListener(e -> roundedSelectionChanged());
+			tableOptionsPanel.add(roundedSelectionCheckBox, "cell 0 0");
+
 			//---- showHorizontalLinesCheckBox ----
 			showHorizontalLinesCheckBox.setText("show horizontal lines");
 			showHorizontalLinesCheckBox.addActionListener(e -> showHorizontalLinesChanged());
-			tableOptionsPanel.add(showHorizontalLinesCheckBox, "cell 0 0");
+			tableOptionsPanel.add(showHorizontalLinesCheckBox, "cell 0 1");
 
 			//---- showVerticalLinesCheckBox ----
 			showVerticalLinesCheckBox.setText("show vertical lines");
 			showVerticalLinesCheckBox.addActionListener(e -> showVerticalLinesChanged());
-			tableOptionsPanel.add(showVerticalLinesCheckBox, "cell 0 1");
+			tableOptionsPanel.add(showVerticalLinesCheckBox, "cell 0 2");
 
 			//---- intercellSpacingCheckBox ----
 			intercellSpacingCheckBox.setText("intercell spacing");
 			intercellSpacingCheckBox.addActionListener(e -> intercellSpacingChanged());
-			tableOptionsPanel.add(intercellSpacingCheckBox, "cell 0 2");
+			tableOptionsPanel.add(intercellSpacingCheckBox, "cell 0 3");
 
 			//---- redGridColorCheckBox ----
 			redGridColorCheckBox.setText("red grid color");
 			redGridColorCheckBox.addActionListener(e -> redGridColorChanged());
-			tableOptionsPanel.add(redGridColorCheckBox, "cell 0 3");
+			tableOptionsPanel.add(redGridColorCheckBox, "cell 0 4");
 
 			//---- rowSelectionCheckBox ----
 			rowSelectionCheckBox.setText("row selection");
 			rowSelectionCheckBox.setSelected(true);
 			rowSelectionCheckBox.addActionListener(e -> rowSelectionChanged());
-			tableOptionsPanel.add(rowSelectionCheckBox, "cell 0 4");
+			tableOptionsPanel.add(rowSelectionCheckBox, "cell 0 5");
 
 			//---- columnSelectionCheckBox ----
 			columnSelectionCheckBox.setText("column selection");
 			columnSelectionCheckBox.addActionListener(e -> columnSelectionChanged());
-			tableOptionsPanel.add(columnSelectionCheckBox, "cell 0 5");
+			tableOptionsPanel.add(columnSelectionCheckBox, "cell 0 6");
+
+			//---- alternatingRowsCheckBox ----
+			alternatingRowsCheckBox.setText("alternating rows");
+			alternatingRowsCheckBox.addActionListener(e -> alternatingRowsChanged());
+			tableOptionsPanel.add(alternatingRowsCheckBox, "cell 0 7");
 
 			//---- dndCheckBox ----
 			dndCheckBox.setText("enable drag and drop");
 			dndCheckBox.setMnemonic('D');
 			dndCheckBox.addActionListener(e -> dndChanged());
-			tableOptionsPanel.add(dndCheckBox, "cell 0 6");
+			tableOptionsPanel.add(dndCheckBox, "cell 0 8");
 		}
 		add(tableOptionsPanel, "cell 4 3");
 
@@ -477,12 +517,14 @@ class DataComponentsPanel
 	private JTree tree3;
 	private JTree tree2;
 	private JTable table1;
+	private JCheckBox roundedSelectionCheckBox;
 	private JCheckBox showHorizontalLinesCheckBox;
 	private JCheckBox showVerticalLinesCheckBox;
 	private JCheckBox intercellSpacingCheckBox;
 	private JCheckBox redGridColorCheckBox;
 	private JCheckBox rowSelectionCheckBox;
 	private JCheckBox columnSelectionCheckBox;
+	private JCheckBox alternatingRowsCheckBox;
 	private JCheckBox dndCheckBox;
 	// JFormDesigner - End of variables declaration  //GEN-END:variables
 

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DataComponentsPanel.jfd

@@ -343,9 +343,19 @@ new FormModel {
 			add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 				"$layoutConstraints": "insets 0,hidemode 3"
 				"$columnConstraints": "[]"
-				"$rowConstraints": "[]0[]0[]0[]0[]0[]0[]0"
+				"$rowConstraints": "[]0[]0[]0[]0[]0[]0[]0[]0[]0"
 			} ) {
 				name: "tableOptionsPanel"
+				add( new FormComponent( "javax.swing.JCheckBox" ) {
+					name: "roundedSelectionCheckBox"
+					"text": "rounded selection"
+					auxiliary() {
+						"JavaCodeGenerator.variableLocal": false
+					}
+					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "roundedSelectionChanged", false ) )
+				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+					"value": "cell 0 0"
+				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "showHorizontalLinesCheckBox"
 					"text": "show horizontal lines"
@@ -354,7 +364,7 @@ new FormModel {
 					}
 					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "showHorizontalLinesChanged", false ) )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 0"
+					"value": "cell 0 1"
 				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "showVerticalLinesCheckBox"
@@ -364,7 +374,7 @@ new FormModel {
 					}
 					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "showVerticalLinesChanged", false ) )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 1"
+					"value": "cell 0 2"
 				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "intercellSpacingCheckBox"
@@ -374,7 +384,7 @@ new FormModel {
 					}
 					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "intercellSpacingChanged", false ) )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 2"
+					"value": "cell 0 3"
 				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "redGridColorCheckBox"
@@ -384,7 +394,7 @@ new FormModel {
 					}
 					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "redGridColorChanged", false ) )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 3"
+					"value": "cell 0 4"
 				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "rowSelectionCheckBox"
@@ -395,7 +405,7 @@ new FormModel {
 					}
 					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "rowSelectionChanged", false ) )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 4"
+					"value": "cell 0 5"
 				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "columnSelectionCheckBox"
@@ -405,7 +415,17 @@ new FormModel {
 					}
 					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "columnSelectionChanged", false ) )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 5"
+					"value": "cell 0 6"
+				} )
+				add( new FormComponent( "javax.swing.JCheckBox" ) {
+					name: "alternatingRowsCheckBox"
+					"text": "alternating rows"
+					auxiliary() {
+						"JavaCodeGenerator.variableLocal": false
+					}
+					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "alternatingRowsChanged", false ) )
+				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+					"value": "cell 0 7"
 				} )
 				add( new FormComponent( "javax.swing.JCheckBox" ) {
 					name: "dndCheckBox"
@@ -416,7 +436,7 @@ new FormModel {
 					}
 					addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "dndChanged", false ) )
 				}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
-					"value": "cell 0 6"
+					"value": "cell 0 8"
 				} )
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 4 3"

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/DemoPrefs.java

@@ -19,6 +19,10 @@ package com.formdev.flatlaf.demo;
 import java.io.File;
 import java.io.FileInputStream;
 import java.util.prefs.Preferences;
+import javax.swing.JComponent;
+import javax.swing.JFrame;
+import javax.swing.JOptionPane;
+import javax.swing.KeyStroke;
 import javax.swing.UIManager;
 import com.formdev.flatlaf.FlatLaf;
 import com.formdev.flatlaf.FlatLightLaf;
@@ -27,6 +31,7 @@ import com.formdev.flatlaf.IntelliJTheme;
 import com.formdev.flatlaf.demo.intellijthemes.IJThemesPanel;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.StringUtils;
+import com.formdev.flatlaf.util.SystemInfo;
 
 /**
  * @author Karl Tauber
@@ -35,6 +40,7 @@ public class DemoPrefs
 {
 	public static final String KEY_LAF = "laf";
 	public static final String KEY_LAF_THEME = "lafTheme";
+	public static final String KEY_SYSTEM_SCALE_FACTOR = "systemScaleFactor";
 
 	public static final String RESOURCE_PREFIX = "res:";
 	public static final String FILE_PREFIX = "file:";
@@ -96,4 +102,66 @@ public class DemoPrefs
 				state.put( KEY_LAF, UIManager.getLookAndFeel().getClass().getName() );
 		} );
 	}
+
+	public static void initSystemScale() {
+		if( System.getProperty( "sun.java2d.uiScale" ) == null ) {
+			String scaleFactor = getState().get( KEY_SYSTEM_SCALE_FACTOR, null );
+			if( scaleFactor != null )
+				System.setProperty( "sun.java2d.uiScale", scaleFactor );
+		}
+	}
+
+	/**
+	 * register Alt+Shift+F1, F2, ... F12 keys to change system scale factor
+	 */
+	public static void registerSystemScaleFactors( JFrame frame ) {
+		registerSystemScaleFactor( frame, "alt shift F1", null );
+		registerSystemScaleFactor( frame, "alt shift F2", "1" );
+
+		if( SystemInfo.isWindows ) {
+			registerSystemScaleFactor( frame, "alt shift F3", "1.25" );
+			registerSystemScaleFactor( frame, "alt shift F4", "1.5" );
+			registerSystemScaleFactor( frame, "alt shift F5", "1.75" );
+			registerSystemScaleFactor( frame, "alt shift F6", "2" );
+			registerSystemScaleFactor( frame, "alt shift F7", "2.25" );
+			registerSystemScaleFactor( frame, "alt shift F8", "2.5" );
+			registerSystemScaleFactor( frame, "alt shift F9", "2.75" );
+			registerSystemScaleFactor( frame, "alt shift F10", "3" );
+			registerSystemScaleFactor( frame, "alt shift F11", "3.5" );
+			registerSystemScaleFactor( frame, "alt shift F12", "4" );
+		} else {
+			// Java on macOS and Linux supports only integer scale factors
+			registerSystemScaleFactor( frame, "alt shift F3", "2" );
+			registerSystemScaleFactor( frame, "alt shift F4", "3" );
+			registerSystemScaleFactor( frame, "alt shift F5", "4" );
+
+		}
+	}
+
+	private static void registerSystemScaleFactor( JFrame frame, String keyStrokeStr, String scaleFactor ) {
+		KeyStroke keyStroke = KeyStroke.getKeyStroke( keyStrokeStr );
+		if( keyStroke == null )
+			throw new IllegalArgumentException( "Invalid key stroke '" + keyStrokeStr + "'" );
+
+		((JComponent)frame.getContentPane()).registerKeyboardAction(
+			e -> applySystemScaleFactor( frame, scaleFactor ),
+			keyStroke,
+			JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT );
+	}
+
+	private static void applySystemScaleFactor( JFrame frame, String scaleFactor ) {
+		if( JOptionPane.showConfirmDialog( frame,
+				"Change system scale factor to "
+				+ (scaleFactor != null ? scaleFactor : "default")
+				+ " and exit?",
+				frame.getTitle(), JOptionPane.YES_NO_OPTION ) != JOptionPane.YES_OPTION )
+			return;
+
+		if( scaleFactor != null )
+			DemoPrefs.getState().put( KEY_SYSTEM_SCALE_FACTOR, scaleFactor );
+		else
+			DemoPrefs.getState().remove( KEY_SYSTEM_SCALE_FACTOR );
+
+		System.exit( 0 );
+	}
 }

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/FlatLafDemo.java

@@ -70,9 +70,10 @@ public class FlatLafDemo
 		if( FlatLafDemo.screenshotsMode && !SystemInfo.isJava_9_orLater && System.getProperty( "flatlaf.uiScale" ) == null )
 			System.setProperty( "flatlaf.uiScale", "2x" );
 
-		SwingUtilities.invokeLater( () -> {
 		DemoPrefs.init( PREFS_ROOT_PATH );
+		DemoPrefs.initSystemScale();
 
+		SwingUtilities.invokeLater( () -> {
 			// install fonts for lazy loading
 			FlatInterFont.installLazy();
 			FlatJetBrainsMonoFont.installLazy();
@@ -95,6 +96,9 @@ public class FlatLafDemo
 			// use Roboto Mono font
 //			FlatLaf.setPreferredMonospacedFontFamily( FlatRobotoMonoFont.FAMILY );
 
+			// install own repaint manager to fix repaint issues at 125%, 175%, 225%, ... on Windows
+//			HiDPIUtils.installHiDPIRepaintManager();
+
 			// application specific UI defaults
 			FlatLaf.registerCustomDefaultsSource( "com.formdev.flatlaf.demo" );
 

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/MoreComponentsPanel.java

@@ -118,6 +118,14 @@ class MoreComponentsPanel
 		JLabel label5 = new JLabel();
 		JPanel panel13 = new JPanel();
 		JLabel label6 = new JLabel();
+		JLabel panelLabel = new JLabel();
+		JPanel panel5 = new JPanel();
+		JLabel label9 = new JLabel();
+		JPanel panel4 = new JPanel();
+		JLabel label8 = new JLabel();
+		JLabel labelLabel = new JLabel();
+		JLabel label13 = new JLabel();
+		JLabel label10 = new JLabel();
 
 		//======== this ========
 		setLayout(new MigLayout(
@@ -140,7 +148,9 @@ class MoreComponentsPanel
 			"[]" +
 			"[]" +
 			"[]" +
-			"[100,top]"));
+			"[100,top]" +
+			"[50,top]" +
+			"[]"));
 
 		//---- scrollPaneLabel ----
 		scrollPaneLabel.setText("JScrollPane:");
@@ -441,7 +451,7 @@ class MoreComponentsPanel
 
 				//======== panel10 ========
 				{
-					panel10.setBackground(new Color(217, 163, 67));
+					panel10.setBackground(new Color(0xd9a343));
 					panel10.setLayout(new BorderLayout());
 
 					//---- label1 ----
@@ -454,7 +464,7 @@ class MoreComponentsPanel
 
 				//======== panel11 ========
 				{
-					panel11.setBackground(new Color(98, 181, 67));
+					panel11.setBackground(new Color(0x62b543));
 					panel11.setLayout(new BorderLayout());
 
 					//---- label2 ----
@@ -474,7 +484,7 @@ class MoreComponentsPanel
 
 				//======== panel12 ========
 				{
-					panel12.setBackground(new Color(242, 101, 34));
+					panel12.setBackground(new Color(0xf26522));
 					panel12.setLayout(new BorderLayout());
 
 					//---- label5 ----
@@ -487,7 +497,7 @@ class MoreComponentsPanel
 
 				//======== panel13 ========
 				{
-					panel13.setBackground(new Color(64, 182, 224));
+					panel13.setBackground(new Color(0x40b6e0));
 					panel13.setLayout(new BorderLayout());
 
 					//---- label6 ----
@@ -502,6 +512,52 @@ class MoreComponentsPanel
 		}
 		add(splitPane3, "cell 1 11 4 1,grow");
 
+		//---- panelLabel ----
+		panelLabel.setText("JPanel:");
+		add(panelLabel, "cell 0 12");
+
+		//======== panel5 ========
+		{
+			panel5.putClientProperty("FlatLaf.style", "arc: 16; background: darken($Panel.background,5%)");
+			panel5.setLayout(new BorderLayout());
+
+			//---- label9 ----
+			label9.setText("rounded background");
+			label9.setHorizontalAlignment(SwingConstants.CENTER);
+			panel5.add(label9, BorderLayout.CENTER);
+		}
+		add(panel5, "cell 1 12 4 1,growy,width 150");
+
+		//======== panel4 ========
+		{
+			panel4.putClientProperty("FlatLaf.style", "border: 1,1,1,1,@disabledForeground,1,16; background: darken($Panel.background,5%)");
+			panel4.setLayout(new BorderLayout());
+
+			//---- label8 ----
+			label8.setText("rounded border");
+			label8.setHorizontalAlignment(SwingConstants.CENTER);
+			panel4.add(label8, BorderLayout.CENTER);
+		}
+		add(panel4, "cell 1 12 4 1,growy,width 150");
+
+		//---- labelLabel ----
+		labelLabel.setText("JLabel:");
+		add(labelLabel, "cell 0 13");
+
+		//---- label13 ----
+		label13.setText("rounded background");
+		label13.putClientProperty("FlatLaf.style", "arc: 999; border: 2,10,2,10");
+		label13.setBackground(new Color(0xb8e4f3));
+		label13.setForeground(new Color(0x135b76));
+		add(label13, "cell 1 13 4 1");
+
+		//---- label10 ----
+		label10.setText("rounded border");
+		label10.putClientProperty("FlatLaf.style", "arc: 999; border: 2,10,2,10,#135b76");
+		label10.setBackground(new Color(0xb8e4f3));
+		label10.setForeground(new Color(0x135b76));
+		add(label10, "cell 1 13 4 1");
+
 		//---- buttonGroup1 ----
 		ButtonGroup buttonGroup1 = new ButtonGroup();
 		buttonGroup1.add(toggleButton1);

flatlaf-demo/src/main/java/com/formdev/flatlaf/demo/MoreComponentsPanel.jfd

@@ -1,4 +1,4 @@
-JFDML JFormDesigner: "7.0.5.0.404" Java: "17.0.2" encoding: "UTF-8"
+JFDML JFormDesigner: "8.2.2.0.9999" Java: "21.0.1" encoding: "UTF-8"
 
 new FormModel {
 	contentType: "form/swing"
@@ -9,7 +9,7 @@ new FormModel {
 		add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
 			"$layoutConstraints": "insets dialog,hidemode 3"
 			"$columnConstraints": "[][][][][]"
-			"$rowConstraints": "[][][][][][][][][][][][100,top]"
+			"$rowConstraints": "[][][][][][][][][][][][100,top][50,top][]"
 		} ) {
 			name: "this"
 			add( new FormComponent( "javax.swing.JLabel" ) {
@@ -467,6 +467,62 @@ new FormModel {
 			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
 				"value": "cell 1 11 4 1,grow"
 			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "panelLabel"
+				"text": "JPanel:"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 0 12"
+			} )
+			add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class java.awt.BorderLayout ) ) {
+				name: "panel5"
+				"$client.FlatLaf.style": "arc: 16; background: darken($Panel.background,5%)"
+				add( new FormComponent( "javax.swing.JLabel" ) {
+					name: "label9"
+					"text": "rounded background"
+					"horizontalAlignment": 0
+				}, new FormLayoutConstraints( class java.lang.String ) {
+					"value": "Center"
+				} )
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 12 4 1,growy,width 150"
+			} )
+			add( new FormContainer( "javax.swing.JPanel", new FormLayoutManager( class java.awt.BorderLayout ) ) {
+				name: "panel4"
+				"$client.FlatLaf.style": "border: 1,1,1,1,@disabledForeground,1,16; background: darken($Panel.background,5%)"
+				add( new FormComponent( "javax.swing.JLabel" ) {
+					name: "label8"
+					"text": "rounded border"
+					"horizontalAlignment": 0
+				}, new FormLayoutConstraints( class java.lang.String ) {
+					"value": "Center"
+				} )
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 12 4 1,growy,width 150"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "labelLabel"
+				"text": "JLabel:"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 0 13"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "label13"
+				"text": "rounded background"
+				"$client.FlatLaf.style": "arc: 999; border: 2,10,2,10"
+				"background": new java.awt.Color( 184, 228, 243, 255 )
+				"foreground": new java.awt.Color( 19, 91, 118, 255 )
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 13 4 1"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "label10"
+				"text": "rounded border"
+				"$client.FlatLaf.style": "arc: 999; border: 2,10,2,10,#135b76"
+				"background": new java.awt.Color( 184, 228, 243, 255 )
+				"foreground": new java.awt.Color( 19, 91, 118, 255 )
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 13 4 1"
+			} )
 		}, new FormLayoutConstraints( null ) {
 			"location": new java.awt.Point( 0, 0 )
 			"size": new java.awt.Dimension( 700, 550 )
@@ -474,7 +530,7 @@ new FormModel {
 		add( new FormNonVisual( "javax.swing.ButtonGroup" ) {
 			name: "buttonGroup1"
 		}, new FormLayoutConstraints( null ) {
-			"location": new java.awt.Point( 0, 560 )
+			"location": new java.awt.Point( 0, 600 )
 		} )
 	}
 }

flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/FlatInspector.java

@@ -547,6 +547,12 @@ public class FlatInspector
 		appendRow( buf, "Left-to-right", String.valueOf( c.getComponentOrientation().isLeftToRight() ) );
 		appendRow( buf, "Parent", (c.getParent() != null ? toString( c.getParent().getClass(), classHierarchy ) : "null") );
 
+		if( c instanceof JComponent ) {
+			Object style = ((JComponent)c).getClientProperty( FlatClientProperties.STYLE );
+			if( style != null )
+				appendRow( buf, "FlatLaf Style", style.toString() );
+		}
+
 		// append parent level
 		buf.append( "<tr><td colspan=\"2\">" );
 		if( parentLevel > 0 )

flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/FlatSVGIcon.java

@@ -25,6 +25,7 @@ import java.awt.Image;
 import java.awt.Paint;
 import java.awt.Rectangle;
 import java.awt.RenderingHints;
+import java.awt.LinearGradientPaint;
 import java.awt.image.BufferedImage;
 import java.awt.image.RGBImageFilter;
 import java.io.File;
@@ -62,6 +63,8 @@ public class FlatSVGIcon
 	extends ImageIcon
 	implements DisabledIconProvider
 {
+	private static boolean loggingEnabled = true;
+	private static boolean svgCacheEnabled = true;
 	// cache that uses soft references for values, which allows freeing SVG documents if no longer used
 	private static final SoftCache<String, SVGDocument> svgCache = new SoftCache<>();
 	private static final SVGLoader svgLoader = new SVGLoader();
@@ -271,7 +274,8 @@ public class FlatSVGIcon
 
 			if( document == null ) {
 				loadFailed = true;
-				LoggingFacade.INSTANCE.logSevere( "FlatSVGIcon: failed to load SVG icon from input stream", null );
+				if( loggingEnabled )
+					LoggingFacade.INSTANCE.logConfig( "FlatSVGIcon: failed to load SVG icon from input stream", null );
 			}
 		}
 	}
@@ -449,8 +453,9 @@ public class FlatSVGIcon
 	 * @param colorFilter The color filter
 	 * @since 1.2
 	 */
-	public void setColorFilter( ColorFilter colorFilter ) {
+	public FlatSVGIcon setColorFilter( ColorFilter colorFilter ) {
 		this.colorFilter = colorFilter;
+		return this;
 	}
 
 	private void update() {
@@ -474,6 +479,7 @@ public class FlatSVGIcon
 
 			if( url == null ) {
 				loadFailed = true;
+				if( loggingEnabled )
 					LoggingFacade.INSTANCE.logConfig( "FlatSVGIcon: resource '" + name + "' not found (if using Java modules, check whether icon package is opened in module-info.java)", null );
 				return;
 			}
@@ -484,6 +490,9 @@ public class FlatSVGIcon
 	}
 
 	static synchronized SVGDocument loadSVG( URL url ) {
+		if( !svgCacheEnabled )
+			return loadSVGUncached( url );
+
 		// get from our cache
 		String cacheKey = url.toString();
 		SVGDocument document = svgCache.get( cacheKey );
@@ -491,18 +500,25 @@ public class FlatSVGIcon
 			return document;
 
 		// load SVG document
-		document = svgLoader.load( url );
-
-		if( document == null ) {
-			LoggingFacade.INSTANCE.logSevere( "FlatSVGIcon: failed to load '" + url + "'", null );
-			return null;
-		}
+		document = loadSVGUncached( url );
 
 		svgCache.put( cacheKey, document );
 
 		return document;
 	}
 
+	private static SVGDocument loadSVGUncached( URL url ) {
+		SVGDocument document = svgLoader.load( url );
+
+		if( document == null ) {
+			if( loggingEnabled )
+				LoggingFacade.INSTANCE.logConfig( "FlatSVGIcon: failed to load '" + url + "'", null );
+			return null;
+		}
+
+		return document;
+	}
+
 	private URL getIconURL( String name, boolean dark ) {
 		if( dark ) {
 			int dotIndex = name.lastIndexOf( '.' );
@@ -611,6 +627,9 @@ public class FlatSVGIcon
 	}
 
 	private void paintSvgError( Graphics2D g, int x, int y ) {
+		if( g instanceof GraphicsFilter )
+			((GraphicsFilter)g).setColorUnfiltered( Color.red );
+		else
 			g.setColor( Color.red );
 		g.fillRect( x, y, getIconWidth(), getIconHeight() );
 	}
@@ -692,6 +711,34 @@ public class FlatSVGIcon
 		darkLaf = FlatLaf.isLafDark();
 	}
 
+	/** @since 3.4.1 */
+	public static boolean isLoggingEnabled() {
+		return loggingEnabled;
+	}
+
+	/** @since 3.4.1 */
+	public static void setLoggingEnabled( boolean loggingEnabled ) {
+		FlatSVGIcon.loggingEnabled = loggingEnabled;
+	}
+
+	/** @since 3.4.1 */
+	public static boolean isSVGDocumentEnabled() {
+		return svgCacheEnabled;
+	}
+
+	/** @since 3.4.1 */
+	public static void setSVGDocumentEnabled( boolean svgCacheEnabled ) {
+		FlatSVGIcon.svgCacheEnabled = svgCacheEnabled;
+
+		if( !svgCacheEnabled )
+			clearSVGDocumentCache();
+	}
+
+	/** @since 3.4.1 */
+	public static void clearSVGDocumentCache() {
+		svgCache.clear();
+	}
+
 	//---- class ColorFilter --------------------------------------------------
 
 	/**
@@ -978,10 +1025,23 @@ public class FlatSVGIcon
 			super.setColor( filterColor( c ) );
 		}
 
+		void setColorUnfiltered( Color c ) {
+			super.setColor( c );
+		}
+
 		@Override
 		public void setPaint( Paint paint ) {
 			if( paint instanceof Color )
 				paint = filterColor( (Color) paint );
+			else if( paint instanceof LinearGradientPaint ) {
+				LinearGradientPaint oldPaint = (LinearGradientPaint) paint;
+				Color[] newColors = filterColors( oldPaint.getColors() );
+				if( newColors != null ) {
+					paint = new LinearGradientPaint( oldPaint.getStartPoint(), oldPaint.getEndPoint(),
+						oldPaint.getFractions(), newColors, oldPaint.getCycleMethod(),
+						oldPaint.getColorSpace(), oldPaint.getTransform() );
+				}
+			}
 			super.setPaint( paint );
 		}
 
@@ -1001,5 +1061,15 @@ public class FlatSVGIcon
 			}
 			return color;
 		}
+
+		private Color[] filterColors( Color[] colors ) {
+			Color[] newColors = new Color[colors.length];
+			boolean changed = false;
+			for( int i = 0; i < colors.length; i++ ) {
+				newColors[i] = filterColor( colors[i] );
+				changed = (changed || newColors[i] != colors[i]);
+			}
+			return changed ? newColors : null;
+		}
 	}
 }

flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/components/FlatSplitPane.java

@@ -16,6 +16,7 @@
 
 package com.formdev.flatlaf.extras.components;
 
+import static com.formdev.flatlaf.FlatClientProperties.*;
 import javax.swing.JSplitPane;
 
 /**
@@ -26,6 +27,29 @@ import javax.swing.JSplitPane;
  */
 public class FlatSplitPane
 	extends JSplitPane
-	implements FlatStyleableComponent
+	implements FlatComponentExtension, FlatStyleableComponent
 {
+	// NOTE: enum names must be equal to allowed strings
+	/** @since 3.4.1 */ public enum ExpandableSide { both, left, right }
+
+	/**
+	 * Returns what side of the spilt pane is allowed to expand
+	 * via one-touch expanding arrow buttons.
+	 *
+	 * @since 3.4.1
+	 */
+	public ExpandableSide getExpandableSide() {
+		return getClientPropertyEnumString( SPLIT_PANE_EXPANDABLE_SIDE, ExpandableSide.class,
+			null, ExpandableSide.both );
+	}
+
+	/**
+	 * Specifies what side of the spilt pane is allowed to expand
+	 * via one-touch expanding arrow buttons.
+	 *
+	 * @since 3.4.1
+	 */
+	public void setExpandableSide( ExpandableSide expandableSide ) {
+		putClientPropertyEnumString( SPLIT_PANE_EXPANDABLE_SIDE, expandableSide );
+	}
 }

flatlaf-fonts/flatlaf-fonts-inter/build.gradle.kts

@@ -33,8 +33,8 @@ plugins {
 dependencies {
 	implementation( project( ":flatlaf-core" ) )
 
-	testImplementation( libs.bundles.junit )
-	testRuntimeOnly( libs.junit.engine )
+	testImplementation( libs.junit )
+	testRuntimeOnly( libs.junit.launcher )
 }
 
 flatlafModuleInfo {
@@ -73,8 +73,8 @@ publishing {
 			pom {
 				licenses {
 					license {
-						name.set( "SIL OPEN FONT LICENSE Version 1.1" )
-						url.set( "https://choosealicense.com/licenses/ofl-1.1/" )
+						name = "SIL OPEN FONT LICENSE Version 1.1"
+						url = "https://choosealicense.com/licenses/ofl-1.1/"
 					}
 				}
 			}

flatlaf-fonts/flatlaf-fonts-jetbrains-mono/build.gradle.kts

@@ -33,8 +33,8 @@ plugins {
 dependencies {
 	implementation( project( ":flatlaf-core" ) )
 
-	testImplementation( libs.bundles.junit )
-	testRuntimeOnly( libs.junit.engine )
+	testImplementation( libs.junit )
+	testRuntimeOnly( libs.junit.launcher )
 }
 
 flatlafModuleInfo {
@@ -73,8 +73,8 @@ publishing {
 			pom {
 				licenses {
 					license {
-						name.set( "SIL OPEN FONT LICENSE Version 1.1" )
-						url.set( "https://choosealicense.com/licenses/ofl-1.1/" )
+						name = "SIL OPEN FONT LICENSE Version 1.1"
+						url = "https://choosealicense.com/licenses/ofl-1.1/"
 					}
 				}
 			}

flatlaf-fonts/flatlaf-fonts-roboto-mono/build.gradle.kts

@@ -33,8 +33,8 @@ plugins {
 dependencies {
 	implementation( project( ":flatlaf-core" ) )
 
-	testImplementation( libs.bundles.junit )
-	testRuntimeOnly( libs.junit.engine )
+	testImplementation( libs.junit )
+	testRuntimeOnly( libs.junit.launcher )
 }
 
 flatlafModuleInfo {

flatlaf-fonts/flatlaf-fonts-roboto/build.gradle.kts

@@ -33,8 +33,8 @@ plugins {
 dependencies {
 	implementation( project( ":flatlaf-core" ) )
 
-	testImplementation( libs.bundles.junit )
-	testRuntimeOnly( libs.junit.engine )
+	testImplementation( libs.junit )
+	testRuntimeOnly( libs.junit.launcher )
 }
 
 flatlafModuleInfo {

flatlaf-intellij-themes/README.md

@@ -28,10 +28,10 @@ Otherwise, download `flatlaf-intellij-themes-<version>.jar` here:
 How to use?
 -----------
 
-Choose a theme (see list below) and invoke its `install` method. E.g.:
+Choose a theme (see list below) and invoke its `setup` method. E.g.:
 
 ~~~java
-FlatArcOrangeIJTheme.install();
+FlatArcOrangeIJTheme.setup();
 ~~~
 
 

flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatJideButtonUI.java

@@ -16,9 +16,14 @@
 
 package com.formdev.flatlaf.jideoss.ui;
 
+import java.beans.PropertyChangeEvent;
+import javax.swing.AbstractButton;
 import javax.swing.JComponent;
 import javax.swing.plaf.ComponentUI;
+import javax.swing.plaf.basic.BasicButtonListener;
+import com.formdev.flatlaf.ui.FlatHTML;
 import com.jidesoft.plaf.LookAndFeelFactory;
+import com.jidesoft.plaf.basic.BasicJideButtonListener;
 import com.jidesoft.plaf.basic.BasicJideButtonUI;
 
 /**
@@ -37,4 +42,26 @@ public class FlatJideButtonUI
 
 		return new FlatJideButtonUI();
 	}
+
+	@Override
+	protected BasicButtonListener createButtonListener( AbstractButton b ) {
+		return new FlatJideButtonListener( b );
+	}
+
+	//---- class FlatJideButtonListener ---------------------------------------
+
+	/** @since 3.5 */
+	protected static class FlatJideButtonListener
+		extends BasicJideButtonListener
+	{
+		protected FlatJideButtonListener( AbstractButton b ) {
+			super( b );
+		}
+
+		@Override
+		public void propertyChange( PropertyChangeEvent e ) {
+			super.propertyChange( e );
+			FlatHTML.propertyChange( e );
+		}
+	}
 }

flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatJideLabelUI.java

@@ -18,11 +18,13 @@ package com.formdev.flatlaf.jideoss.ui;
 
 import java.awt.Color;
 import java.awt.Graphics;
+import java.beans.PropertyChangeEvent;
 import javax.swing.JComponent;
 import javax.swing.JLabel;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import com.formdev.flatlaf.FlatLaf;
+import com.formdev.flatlaf.ui.FlatHTML;
 import com.formdev.flatlaf.ui.FlatUIUtils;
 import com.jidesoft.plaf.LookAndFeelFactory;
 import com.jidesoft.plaf.basic.BasicJideLabelUI;
@@ -65,6 +67,20 @@ public class FlatJideLabelUI
 		defaults_initialized = false;
 	}
 
+	@Override
+	protected void installComponents( JLabel c ) {
+		super.installComponents( c );
+
+		// update HTML renderer if necessary
+		FlatHTML.updateRendererCSSFontBaseSize( c );
+	}
+
+	@Override
+	public void propertyChange( PropertyChangeEvent e ) {
+		super.propertyChange( e );
+		FlatHTML.propertyChange( e );
+	}
+
 	@Override
 	protected void paintEnabledText( JLabel l, Graphics g, String s, int textX, int textY ) {
 		int mnemIndex = FlatLaf.isShowMnemonics() ? l.getDisplayedMnemonicIndex() : -1;

flatlaf-natives/flatlaf-natives-jna/src/main/java/com/formdev/flatlaf/natives/jna/windows/FlatWindowsNativeWindowBorder.java

@@ -60,8 +60,11 @@ import com.sun.jna.platform.win32.WinDef.LRESULT;
 import com.sun.jna.platform.win32.WinDef.RECT;
 import com.sun.jna.platform.win32.WinDef.UINT_PTR;
 import com.sun.jna.platform.win32.WinDef.WPARAM;
+import com.sun.jna.platform.win32.WinError;
 import com.sun.jna.platform.win32.WinUser.HMONITOR;
 import com.sun.jna.platform.win32.WinUser.WindowProc;
+import com.sun.jna.ptr.IntByReference;
+import com.sun.jna.win32.StdCallLibrary;
 import com.sun.jna.win32.W32APIOptions;
 
 //
@@ -615,6 +618,14 @@ public class FlatWindowsNativeWindowBorder
 					if( hasAutohideTaskbar( ABE_RIGHT, monitorInfo.rcMonitor ) )
 						params.rgrc[0].right--;
 				}
+			} else if( SystemInfo.isWindows_11_orLater ) {
+				// For Windows 11, add border thickness to top, which is necessary to make the whole Java area visible.
+				// This also avoids that a black line is sometimes painted on top window border.
+				// Note: Do not increase top on Windows 10 because this would not hide Windows title bar.
+				IntByReference borderThickness = new IntByReference();
+				if( DWMApi.INSTANCE.DwmGetWindowAttribute( hwnd, DWMApi.DWMWA_VISIBLE_FRAME_BORDER_THICKNESS,
+						borderThickness.getPointer(), 4 ) == WinError.S_OK.intValue() )
+					params.rgrc[0].top += borderThickness.getValue();
 			}
 
 			// write changed params back to native memory
@@ -898,6 +909,18 @@ public class FlatWindowsNativeWindowBorder
 		HBRUSH CreateSolidBrush( DWORD color );
 	}
 
+	//---- interface DWMApi ---------------------------------------------------
+
+	private interface DWMApi
+		extends StdCallLibrary
+	{
+		DWMApi INSTANCE = Native.load( "dwmapi", DWMApi.class, W32APIOptions.DEFAULT_OPTIONS );
+
+		int DWMWA_VISIBLE_FRAME_BORDER_THICKNESS = 37;
+
+		int DwmGetWindowAttribute( HWND hwnd, int dwAttribute, Pointer pvAttribute, int cbAttribute );
+	}
+
 	//---- class NCCALCSIZE_PARAMS --------------------------------------------
 
 	@FieldOrder( { "rgrc" } )

flatlaf-natives/flatlaf-natives-linux/build.gradle.kts

@@ -21,11 +21,14 @@ plugins {
 }
 
 flatlafJniHeaders {
-	headers = listOf( "com_formdev_flatlaf_ui_FlatNativeLinuxLibrary.h" )
+	headers = listOf(
+		"com_formdev_flatlaf_ui_FlatNativeLibrary.h",
+		"com_formdev_flatlaf_ui_FlatNativeLinuxLibrary.h"
+	)
 }
 
 library {
-	targetMachines.set( listOf( machines.linux.x86_64 ) )
+	targetMachines = listOf( machines.linux.x86_64 )
 }
 
 var javaHome = System.getProperty( "java.home" )

flatlaf-natives/flatlaf-natives-linux/src/main/cpp/ApiVersion.cpp

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2024 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <jni.h>
+#include "com_formdev_flatlaf_ui_FlatNativeLibrary.h"
+
+/**
+ * @author Karl Tauber
+ */
+
+
+// increase this version if changing API or functionality of native library
+// also update version in Java class com.formdev.flatlaf.ui.FlatNativeLinuxLibrary
+#define API_VERSION_LINUX		3001
+
+
+//---- JNI methods ------------------------------------------------------------
+
+extern "C"
+JNIEXPORT jint JNICALL Java_com_formdev_flatlaf_ui_FlatNativeLibrary_getApiVersion
+	( JNIEnv* env, jclass cls )
+{
+	return API_VERSION_LINUX;
+}

flatlaf-natives/flatlaf-natives-linux/src/main/headers/com_formdev_flatlaf_ui_FlatNativeLibrary.h

@@ -0,0 +1,21 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+/* Header for class com_formdev_flatlaf_ui_FlatNativeLibrary */
+
+#ifndef _Included_com_formdev_flatlaf_ui_FlatNativeLibrary
+#define _Included_com_formdev_flatlaf_ui_FlatNativeLibrary
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Class:     com_formdev_flatlaf_ui_FlatNativeLibrary
+ * Method:    getApiVersion
+ * Signature: ()I
+ */
+JNIEXPORT jint JNICALL Java_com_formdev_flatlaf_ui_FlatNativeLibrary_getApiVersion
+  (JNIEnv *, jclass);
+
+#ifdef __cplusplus
+}
+#endif
+#endif

flatlaf-natives/flatlaf-natives-macos/build.gradle.kts

@@ -26,14 +26,17 @@ plugins {
 }
 
 flatlafJniHeaders {
-	headers = listOf( "com_formdev_flatlaf_ui_FlatNativeMacLibrary.h" )
+	headers = listOf(
+		"com_formdev_flatlaf_ui_FlatNativeLibrary.h",
+		"com_formdev_flatlaf_ui_FlatNativeMacLibrary.h"
+	)
 }
 
 library {
-	targetMachines.set( listOf(
+	targetMachines = listOf(
 		machines.macOS.architecture( "arm64" ),
 		machines.macOS.x86_64
-	) )
+	)
 }
 
 var javaHome = System.getProperty( "java.home" )

flatlaf-natives/flatlaf-natives-macos/src/main/headers/JNIUtils.h

@@ -42,5 +42,5 @@
 
 
 jclass findClass( JNIEnv *env, const char* className, bool globalRef );
-jfieldID getFieldID( JNIEnv *env, const char* className, const char* fieldName, const char* fieldSignature, bool staticField );
+jfieldID getFieldID( JNIEnv *env, jclass cls, const char* fieldName, const char* fieldSignature, bool staticField );
 jmethodID getMethodID( JNIEnv *env, jclass cls, const char* methodName, const char* methodSignature, bool staticMethod );

flatlaf-natives/flatlaf-natives-macos/src/main/headers/com_formdev_flatlaf_ui_FlatNativeLibrary.h

@@ -0,0 +1,21 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+/* Header for class com_formdev_flatlaf_ui_FlatNativeLibrary */
+
+#ifndef _Included_com_formdev_flatlaf_ui_FlatNativeLibrary
+#define _Included_com_formdev_flatlaf_ui_FlatNativeLibrary
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Class:     com_formdev_flatlaf_ui_FlatNativeLibrary
+ * Method:    getApiVersion
+ * Signature: ()I
+ */
+JNIEXPORT jint JNICALL Java_com_formdev_flatlaf_ui_FlatNativeLibrary_getApiVersion
+  (JNIEnv *, jclass);
+
+#ifdef __cplusplus
+}
+#endif
+#endif

flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/ApiVersion.mm

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2024 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <jni.h>
+#include "com_formdev_flatlaf_ui_FlatNativeLibrary.h"
+
+/**
+ * @author Karl Tauber
+ */
+
+
+// increase this version if changing API or functionality of native library
+// also update version in Java class com.formdev.flatlaf.ui.FlatNativeMacLibrary
+#define API_VERSION_MACOS		2001
+
+
+//---- JNI methods ------------------------------------------------------------
+
+extern "C"
+JNIEXPORT jint JNICALL Java_com_formdev_flatlaf_ui_FlatNativeLibrary_getApiVersion
+	( JNIEnv* env, jclass cls )
+{
+	return API_VERSION_MACOS;
+}

flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/JNIUtils.mm

@@ -38,10 +38,9 @@ jclass findClass( JNIEnv *env, const char* className, bool globalRef ) {
 	return cls;
 }
 
-jfieldID getFieldID( JNIEnv *env, const char* className, const char* fieldName, const char* fieldSignature, bool staticField ) {
-//	NSLog( @"getFieldID %s %s %s", className, fieldName, fieldSignature );
+jfieldID getFieldID( JNIEnv *env, jclass cls, const char* fieldName, const char* fieldSignature, bool staticField ) {
+//	NSLog( @"getFieldID %s %s", fieldName, fieldSignature );
 
-	jclass cls = findClass( env, className, false );
 	if( cls == NULL )
 		return NULL;
 
@@ -49,7 +48,7 @@ jfieldID getFieldID( JNIEnv *env, const char* className, const char* fieldName,
 		? env->GetStaticFieldID( cls, fieldName, fieldSignature )
 		: env->GetFieldID( cls, fieldName, fieldSignature );
 	if( fieldID == NULL ) {
-		NSLog( @"FlatLaf: failed to lookup field '%s' of type '%s' in class '%s'", fieldName, fieldSignature, className );
+		NSLog( @"FlatLaf: failed to lookup field '%s' of type '%s'", fieldName, fieldSignature );
 		env->ExceptionDescribe(); // print stack trace
 		env->ExceptionClear();
 		return NULL;

flatlaf-natives/flatlaf-natives-macos/src/main/objcpp/MacWindow.mm

@@ -52,21 +52,27 @@ NSWindow* getNSWindow( JNIEnv* env, jclass cls, jobject window ) {
 	if( window == NULL )
 		return NULL;
 
+	// initialize class IDs (done only once because variables are static)
+	static jclass lwWindowPeerClass = findClass( env, "sun/lwawt/LWWindowPeer", true );
+	static jclass cfRetainedResourceClass = findClass( env, "sun/lwawt/macosx/CFRetainedResource", true );
+	if( lwWindowPeerClass == NULL || cfRetainedResourceClass == NULL )
+		return NULL;
+
 	// initialize field IDs (done only once because variables are static)
-	static jfieldID peerID = getFieldID( env, "java/awt/Component", "peer", "Ljava/awt/peer/ComponentPeer;", false );
-	static jfieldID platformWindowID = getFieldID( env, "sun/lwawt/LWWindowPeer", "platformWindow", "Lsun/lwawt/PlatformWindow;", false );
-	static jfieldID ptrID = getFieldID( env, "sun/lwawt/macosx/CFRetainedResource", "ptr", "J", false );
+	static jfieldID peerID = getFieldID( env, findClass( env, "java/awt/Component", false ), "peer", "Ljava/awt/peer/ComponentPeer;", false );
+	static jfieldID platformWindowID = getFieldID( env, lwWindowPeerClass, "platformWindow", "Lsun/lwawt/PlatformWindow;", false );
+	static jfieldID ptrID = getFieldID( env, cfRetainedResourceClass, "ptr", "J", false );
 	if( peerID == NULL || platformWindowID == NULL || ptrID == NULL )
 		return NULL;
 
 	// get field java.awt.Component.peer
 	jobject peer = env->GetObjectField( window, peerID );
-	if( peer == NULL )
+	if( peer == NULL || !env->IsInstanceOf( peer, lwWindowPeerClass ) )
 		return NULL;
 
 	// get field sun.lwawt.LWWindowPeer.platformWindow
 	jobject platformWindow = env->GetObjectField( peer, platformWindowID );
-	if( platformWindow == NULL )
+	if( platformWindow == NULL || !env->IsInstanceOf( platformWindow, cfRetainedResourceClass ) )
 		return NULL;
 
 	// get field sun.lwawt.macosx.CFRetainedResource.ptr

flatlaf-natives/flatlaf-natives-windows/build.gradle.kts

@@ -22,6 +22,7 @@ plugins {
 
 flatlafJniHeaders {
 	headers = listOf(
+		"com_formdev_flatlaf_ui_FlatNativeLibrary.h",
 		"com_formdev_flatlaf_ui_FlatNativeWindowsLibrary.h",
 		"com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder.h",
 		"com_formdev_flatlaf_ui_FlatWindowsNativeWindowBorder_WndProc.h"
@@ -29,11 +30,11 @@ flatlafJniHeaders {
 }
 
 library {
-	targetMachines.set( listOf(
+	targetMachines = listOf(
 		machines.windows.x86,
 		machines.windows.x86_64,
 		machines.windows.architecture( "aarch64" )
-	) )
+	)
 }
 
 var javaHome = System.getProperty( "java.home" )