macOS fullWindowContent mode:

- added title bar buttons placeholder
- added client property to root pane that contains title bar buttons bounds
- undone toolbar extensions from commit ea2447dcb7

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

@@ -270,6 +270,76 @@ public interface FlatClientProperties
 	String COMPONENT_TITLE_BAR_CAPTION = "JComponent.titleBarCaption";
 
 
+	//---- Panel --------------------------------------------------------------
+
+	/**
+	 * Marks the panel as placeholder for the iconfify/maximize/close buttons
+	 * in fullWindowContent mode.
+	 * <p>
+	 * If fullWindowContent mode is enabled, the preferred size of the panel is equal
+	 * to the size of the iconfify/maximize/close buttons. Otherwise is is {@code 0,0}.
+	 * <p>
+	 * You're responsible to layout that panel at the top-left or top-right corner,
+	 * depending on platform, where the iconfify/maximize/close buttons are located.
+	 * <p>
+	 * Syntax of the value string is: {@code "win|mac [horizontal|vertical]"}.
+	 * <p>
+	 * The string must start with {@code "win"} (for Windows or Linux) or
+	 * with {@code "mac"} (for macOS) and specifies the platform where the placeholder
+	 * should be used. On macOS, you need the placeholder in the top-left corner,
+	 * but on Windows/Linux you need it in the top-right corner. So if fullWindowContent mode
+	 * is supported on both platforms, you can add two placeholders to your layout
+	 * and FlatLaf automatically uses only one of them. The other gets size {@code 0,0}.
+	 * <p>
+	 * Optionally, you can append {@code " horizontal"} or {@code " vertical"} to the value string
+	 * to specify that the placeholder preferred size should be limited to one orientation.
+	 * E.g. {@code "win horizontal"} means that the placeholder preferred width is
+	 * equal to iconfify/maximize/close buttons width, but preferred height is zero.
+	 * <p>
+	 * Example for adding placeholder to top-left corner on macOS:
+	 * <pre>{@code
+	 * JPanel placeholder = new JPanel();
+	 * placeholder.putClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER, "mac" );
+     *
+     * JToolBar toolBar = new JToolBar();
+     * // add tool bar items
+     *
+	 * JPanel toolBarPanel = new JPanel( new BorderLayout() );
+	 * toolBarPanel.add( placeholder, BorderLayout.WEST );
+	 * toolBarPanel.add( toolBar, BorderLayout.CENTER );
+	 *
+	 * frame.getContentPane().add( toolBarPanel, BorderLayout.NORTH );
+	 * }</pre>
+	 *
+	 * Or add placeholder as first item to the tool bar:
+	 * <pre>{@code
+	 * JPanel placeholder = new JPanel();
+	 * placeholder.putClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER, "mac" );
+	 *
+	 * JToolBar toolBar = new JToolBar();
+	 * toolBar.add( placeholder );
+	 * // add tool bar items
+	 *
+	 * frame.getContentPane().add( toolBar, BorderLayout.NORTH );
+	 * }</pre>
+	 *
+	 * If a tabbed pane is located at the top, you can add the placeholder
+	 * as leading component to that tabbed pane:
+	 * <pre>{@code
+	 * JPanel placeholder = new JPanel();
+	 * placeholder.putClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER, "mac" );
+	 *
+	 * tabbedPane.putClientProperty( FlatClientProperties.TABBED_PANE_LEADING_COMPONENT, placeholder );
+	 * }</pre>
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JPanel}<br>
+	 * <strong>Value type</strong> {@link java.lang.String}
+	 *
+	 * @since 3.4
+	 */
+	String FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER = "FlatLaf.fullWindowContent.buttonsPlaceholder";
+
+
 	//---- Popup --------------------------------------------------------------
 
 	/**
@@ -388,6 +458,20 @@ public interface FlatClientProperties
 	 */
 	String MENU_BAR_EMBEDDED = "JRootPane.menuBarEmbedded";
 
+	/**
+	 * Contains the current bounds of the iconfify/maximize/close buttons
+	 * (in root pane coordinates) if fullWindowContent mode is enabled.
+	 * Otherwise its value is {@code null}.
+	 * <p>
+	 * <b>Note</b>: Do not set this client property. It is set by FlatLaf.
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JRootPane}<br>
+	 * <strong>Value type</strong> {@link java.awt.Rectangle}
+	 *
+	 * @since 3.4
+	 */
+	String FULL_WINDOW_CONTENT_BUTTONS_BOUNDS = "FlatLaf.fullWindowContent.buttonsBounds";
+
 	/**
 	 * Specifies whether the window icon should be shown in the window title bar
 	 * (requires enabled window decorations). Default is UI property {@code TitlePane.showIcon}.

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

@@ -16,6 +16,7 @@
 
 package com.formdev.flatlaf.ui;
 
+import java.awt.Rectangle;
 import java.awt.Window;
 
 /**
@@ -54,14 +55,14 @@ public class FlatNativeMacLibrary
 
 	public native static boolean setWindowRoundedBorder( Window window, float radius, float borderWidth, int borderColor );
 
+	/** @since 3.4 */
 	public static final int
 		BUTTON_STYLE_DEFAULT = 0,
 		BUTTON_STYLE_MEDIUM = 1,
 		BUTTON_STYLE_LARGE = 2;
 
-	public native static boolean setWindowButtonStyle( Window window, int buttonStyle );
-	public native static int getWindowButtonAreaWidth( Window window );
-	public native static int getWindowTitleBarHeight( Window window );
-	public native static boolean isWindowFullScreen( Window window );
-	public native static boolean windowToggleFullScreen( Window window );
+	/** @since 3.4 */ public native static boolean setWindowButtonStyle( Window window, int buttonStyle );
+	/** @since 3.4 */ public native static Rectangle getWindowButtonsBounds( Window window );
+	/** @since 3.4 */ public native static boolean isWindowFullScreen( Window window );
+	/** @since 3.4 */ public native static boolean toggleWindowFullScreen( Window window );
 }

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

@@ -16,6 +16,7 @@
 
 package com.formdev.flatlaf.ui;
 
+import java.awt.Dimension;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.beans.PropertyChangeEvent;
@@ -23,6 +24,7 @@ import java.beans.PropertyChangeListener;
 import java.util.Map;
 import javax.swing.JComponent;
 import javax.swing.JPanel;
+import javax.swing.LookAndFeel;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicPanelUI;
 import com.formdev.flatlaf.FlatClientProperties;
@@ -69,6 +71,8 @@ public class FlatPanelUI
 		super.installUI( c );
 
 		c.addPropertyChangeListener( this );
+		if( c.getClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER ) != null )
+			FullWindowContentSupport.registerPlaceholder( c );
 
 		installStyle( (JPanel) c );
 	}
@@ -78,10 +82,20 @@ public class FlatPanelUI
 		super.uninstallUI( c );
 
 		c.removePropertyChangeListener( this );
+		if( c.getClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER ) != null )
+			FullWindowContentSupport.unregisterPlaceholder( c );
 
 		oldStyleValues = null;
 	}
 
+	@Override
+	protected void installDefaults( JPanel p ) {
+		super.installDefaults( p );
+
+		if( p.getClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER ) != null )
+			LookAndFeel.installProperty( p, "opaque", false );
+	}
+
 	/** @since 2.0.1 */
 	@Override
 	public void propertyChange( PropertyChangeEvent e ) {
@@ -98,6 +112,17 @@ public class FlatPanelUI
 				c.revalidate();
 				c.repaint();
 				break;
+
+			case FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER:
+				JPanel p = (JPanel) e.getSource();
+				if( e.getOldValue() != null )
+					FullWindowContentSupport.unregisterPlaceholder( p );
+				if( e.getNewValue() != null )
+					FullWindowContentSupport.registerPlaceholder( p );
+
+				// make panel non-opaque for placeholders
+				LookAndFeel.installProperty( p, "opaque", e.getNewValue() == null );
+				break;
 		}
 	}
 
@@ -162,4 +187,19 @@ public class FlatPanelUI
 
 		paint( g, c );
 	}
+
+	@Override
+	public Dimension getPreferredSize( JComponent c ) {
+		Object value = c.getClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER );
+		if( value != null )
+			return FullWindowContentSupport.getPlaceholderPreferredSize( c, (String) value );
+
+		return super.getPreferredSize( c );
+	}
+
+	@Override
+	public void paint( Graphics g, JComponent c ) {
+		if( c.getClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_PLACEHOLDER ) != null )
+			FullWindowContentSupport.debugPaint( g, c );
+	}
 }

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

@@ -89,6 +89,7 @@ public class FlatRootPaneUI
 	private LayoutManager oldLayout;
 	private PropertyChangeListener ancestorListener;
 	private ComponentListener componentListener;
+	private ComponentListener macFullWindowContentListener;
 
 	public static ComponentUI createUI( JComponent c ) {
 		return new FlatRootPaneUI();
@@ -207,6 +208,9 @@ public class FlatRootPaneUI
 			};
 			root.addPropertyChangeListener( "ancestor", ancestorListener );
 		}
+
+		if( SystemInfo.isMacFullWindowContentSupported )
+			macFullWindowContentListener = FullWindowContentSupport.macInstallListeners( root );
 	}
 
 	@Override
@@ -223,6 +227,11 @@ public class FlatRootPaneUI
 			root.removePropertyChangeListener( "ancestor", ancestorListener );
 			ancestorListener = null;
 		}
+
+		if( SystemInfo.isMacFullWindowContentSupported ) {
+			FullWindowContentSupport.macUninstallListeners( root, macFullWindowContentListener );
+			macFullWindowContentListener = null;
+		}
 	}
 
 	/** @since 1.1.2 */
@@ -359,6 +368,10 @@ public class FlatRootPaneUI
 					titlePane.titleBarColorsChanged();
 				break;
 
+			case FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_BOUNDS:
+				FullWindowContentSupport.revalidatePlaceholders( rootPane );
+				break;
+
 			case FlatClientProperties.GLASS_PANE_FULL_HEIGHT:
 				rootPane.revalidate();
 				break;
@@ -371,26 +384,30 @@ public class FlatRootPaneUI
 			case FlatClientProperties.MACOS_WINDOW_BUTTON_STYLE:
 			case "ancestor":
 				if( SystemInfo.isMacFullWindowContentSupported &&
-					SystemInfo.isJava_17_orLater &&
 					rootPane.isDisplayable() &&
-					FlatClientProperties.clientPropertyBoolean( rootPane, "apple.awt.fullWindowContent", false ) &&
-					FlatNativeMacLibrary.isLoaded() )
+					FlatClientProperties.clientPropertyBoolean( rootPane, "apple.awt.fullWindowContent", false ) )
 				{
-					int buttonStyle = FlatNativeMacLibrary.BUTTON_STYLE_DEFAULT;
-					Object value = rootPane.getClientProperty( FlatClientProperties.MACOS_WINDOW_BUTTON_STYLE );
-					switch( String.valueOf( value ) ) {
-						case FlatClientProperties.MACOS_WINDOW_BUTTON_STYLE_MEDIUM:
-							buttonStyle = FlatNativeMacLibrary.BUTTON_STYLE_MEDIUM;
-							break;
+					// set window button style
+					if( SystemInfo.isJava_17_orLater && FlatNativeMacLibrary.isLoaded() ) {
+						int buttonStyle = FlatNativeMacLibrary.BUTTON_STYLE_DEFAULT;
+						Object value = rootPane.getClientProperty( FlatClientProperties.MACOS_WINDOW_BUTTON_STYLE );
+						switch( String.valueOf( value ) ) {
+							case FlatClientProperties.MACOS_WINDOW_BUTTON_STYLE_MEDIUM:
+								buttonStyle = FlatNativeMacLibrary.BUTTON_STYLE_MEDIUM;
+								break;
 
-						case "true":
-						case FlatClientProperties.MACOS_WINDOW_BUTTON_STYLE_LARGE:
-							buttonStyle = FlatNativeMacLibrary.BUTTON_STYLE_LARGE;
-							break;
+							case "true":
+							case FlatClientProperties.MACOS_WINDOW_BUTTON_STYLE_LARGE:
+								buttonStyle = FlatNativeMacLibrary.BUTTON_STYLE_LARGE;
+								break;
+						}
+
+						Window window = SwingUtilities.windowForComponent( rootPane );
+						FlatNativeMacLibrary.setWindowButtonStyle( window, buttonStyle );
 					}
 
-					Window window = SwingUtilities.windowForComponent( rootPane );
-					FlatNativeMacLibrary.setWindowButtonStyle( window, buttonStyle );
+					// update buttons bounds client property
+					FullWindowContentSupport.macUpdateFullWindowContentButtonsBoundsProperty( rootPane );
 				}
 				break;
 		}

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

@@ -25,7 +25,6 @@ import java.awt.Rectangle;
 import java.util.function.Function;
 import javax.swing.JToolBar;
 import javax.swing.SwingConstants;
-import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
 import javax.swing.plaf.ToolBarUI;
 import com.formdev.flatlaf.util.UIScale;
@@ -115,18 +114,6 @@ public class FlatToolBarBorder
 				insets.top += gripInset;
 		}
 
-		// on macOS, add some extra space to left side for close/minimize/zoom buttons (if necessary)
-		if( c instanceof JToolBar && FlatToolBarUI.isMacOSMainToolbar( (JToolBar) c ) ) {
-			// get button area width from macOS
-			int buttonBarWidth = FlatNativeMacLibrary.isLoaded()
-				? FlatNativeMacLibrary.getWindowButtonAreaWidth( SwingUtilities.windowForComponent( c ) )
-				: -1;
-			if( buttonBarWidth < 0 )
-				buttonBarWidth = 68; // default width if NSWindow does not have a toolbar
-
-			insets.left += buttonBarWidth;
-		}
-
 		return insets;
 	}
 

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

@@ -19,45 +19,35 @@ package com.formdev.flatlaf.ui;
 import java.awt.Color;
 import java.awt.Component;
 import java.awt.Container;
-import java.awt.Dimension;
 import java.awt.FocusTraversalPolicy;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
-import java.awt.LayoutManager;
-import java.awt.LayoutManager2;
 import java.awt.Rectangle;
-import java.awt.Window;
 import java.awt.event.ContainerEvent;
 import java.awt.event.ContainerListener;
-import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.Map;
 import javax.swing.AbstractButton;
-import javax.swing.BoxLayout;
 import javax.swing.ButtonGroup;
 import javax.swing.ButtonModel;
 import javax.swing.DefaultButtonModel;
 import javax.swing.InputMap;
 import javax.swing.JComboBox;
 import javax.swing.JComponent;
-import javax.swing.JRootPane;
 import javax.swing.JToolBar;
 import javax.swing.LayoutFocusTraversalPolicy;
 import javax.swing.RootPaneContainer;
-import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
 import javax.swing.border.Border;
 import javax.swing.plaf.ComponentUI;
-import javax.swing.plaf.UIResource;
 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.LoggingFacade;
-import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
 
 /**
@@ -158,12 +148,6 @@ public class FlatToolBarUI
 			toolBar.setFloatable( false );
 		} else
 			oldFloatable = null;
-
-		// layout manager
-		LayoutManager layout = createLayout();
-		toolBar.setLayout( layout );
-		if( layout instanceof PropertyChangeListener )
-			toolBar.addPropertyChangeListener( (PropertyChangeListener) layout );
 	}
 
 	@Override
@@ -176,8 +160,6 @@ public class FlatToolBarUI
 			toolBar.setFloatable( oldFloatable );
 			oldFloatable = null;
 		}
-
-		toolBar.setLayout( null );
 	}
 
 	@Override
@@ -471,137 +453,6 @@ public class FlatToolBarUI
 			: null;
 	}
 
-	/** @since 3.3 */
-	protected LayoutManager createLayout() {
-		return new FlatToolBarLayoutManager();
-	}
-
-	/**
-	 * Returns whether the given toolbar is used in window titlebar on macOS.
-	 * <p>
-	 * Returns {@code true} if:
-	 * <ul>
-	 *   <li>running on macOS
-	 *   <li>Java supports "full window content"
-	 *   <li>"full window content" is enabled for window
-	 *   <li>toolbar orientation is horizontal
-	 *   <li>toolbar is located at {@code 0,0} in window
-	 * </ul>
-	 *
-	 * @since 3.3
-	 */
-	public static boolean isMacOSMainToolbar( JToolBar toolBar ) {
-		if( !SystemInfo.isMacFullWindowContentSupported ||
-			toolBar.getOrientation() != JToolBar.HORIZONTAL ||
-			toolBar.getX() != 0 ||
-			toolBar.getY() != 0 )
-		  return false;
-
-		JRootPane rootPane = SwingUtilities.getRootPane( toolBar );
-		if( rootPane == null )
-			return false;
-
-		if( !FlatClientProperties.clientPropertyBoolean( rootPane, "apple.awt.fullWindowContent", false ) )
-			return false;
-
-		for( Component p = toolBar.getParent(); p != null && !(p instanceof Window); p = p.getParent() ) {
-			if( p.getX() != 0 || p.getY() != 0 )
-				return false;
-		}
-
-		return true;
-	}
-
-	//---- class FlatToolBarLayoutManager -------------------------------------
-
-	/**
-	 * @since 3.3
-	 */
-	protected class FlatToolBarLayoutManager
-		implements LayoutManager2, PropertyChangeListener, UIResource
-	{
-		private BoxLayout delegate;
-
-		FlatToolBarLayoutManager() {
-			initBoxLayout();
-		}
-
-		private void initBoxLayout() {
-			delegate = new BoxLayout( toolBar, (toolBar.getOrientation() == JToolBar.HORIZONTAL)
-				? BoxLayout.LINE_AXIS : BoxLayout.PAGE_AXIS );
-		}
-
-		@Override
-		public void addLayoutComponent( Component comp, Object constraints ) {
-			delegate.addLayoutComponent( comp, constraints );
-		}
-
-		@Override
-		public void addLayoutComponent( String name, Component comp ) {
-			delegate.addLayoutComponent( name, comp );
-		}
-
-		@Override
-		public void removeLayoutComponent( Component comp ) {
-			delegate.removeLayoutComponent( comp );
-		}
-
-		@Override
-		public Dimension preferredLayoutSize( Container parent ) {
-			return minimumHeightOnMacOS( delegate.preferredLayoutSize( parent ) );
-		}
-
-		@Override
-		public Dimension minimumLayoutSize( Container parent ) {
-			return minimumHeightOnMacOS( delegate.minimumLayoutSize( parent ) );
-		}
-
-		@Override
-		public Dimension maximumLayoutSize( Container target ) {
-			return minimumHeightOnMacOS( delegate.maximumLayoutSize( target ) );
-		}
-
-		private Dimension minimumHeightOnMacOS( Dimension size ) {
-			if( isMacOSMainToolbar( toolBar ) ) {
-				// get title bar height from macOS
-				int titleBarHeight = FlatNativeMacLibrary.isLoaded()
-					? FlatNativeMacLibrary.getWindowTitleBarHeight( SwingUtilities.windowForComponent( toolBar ) )
-					: -1;
-				if( titleBarHeight < 0 )
-					titleBarHeight = 28; // default height if NSWindow does not have a toolbar
-
-				size.height = Math.max( size.height, titleBarHeight );
-			}
-			return size;
-		}
-
-		@Override
-		public void layoutContainer( Container parent ) {
-			delegate.layoutContainer( parent );
-		}
-
-		@Override
-		public void invalidateLayout( Container target ) {
-			delegate.invalidateLayout( target );
-		}
-
-		@Override
-		public float getLayoutAlignmentX( Container target ) {
-			return delegate.getLayoutAlignmentX( target );
-		}
-
-		@Override
-		public float getLayoutAlignmentY( Container target ) {
-			return delegate.getLayoutAlignmentY( target );
-		}
-
-		@Override
-		public void propertyChange( PropertyChangeEvent e ) {
-			if( "orientation".equals( e.getPropertyName() ) )
-				initBoxLayout();
-		}
-	}
-
 	//---- class FlatToolBarFocusTraversalPolicy ------------------------------
 
 	/**

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

@@ -0,0 +1,183 @@
+/*
+ * 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.awt.Component;
+import java.awt.Dimension;
+import java.awt.Graphics;
+import java.awt.Rectangle;
+import java.awt.Window;
+import java.awt.event.ComponentAdapter;
+import java.awt.event.ComponentEvent;
+import java.awt.event.ComponentListener;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Iterator;
+import javax.swing.JComponent;
+import javax.swing.JRootPane;
+import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
+import com.formdev.flatlaf.FlatClientProperties;
+import com.formdev.flatlaf.util.SystemInfo;
+
+/**
+ * @author Karl Tauber
+ */
+class FullWindowContentSupport
+{
+	private static final String KEY_DEBUG_SHOW_PLACEHOLDERS = "FlatLaf.debug.panel.showPlaceholders";
+
+	private static ArrayList<WeakReference<JComponent>> placeholders = new ArrayList<>();
+
+	static Dimension getPlaceholderPreferredSize( JComponent c, String options ) {
+		JRootPane rootPane;
+		Rectangle bounds;
+
+		if( options.startsWith( SystemInfo.isMacOS ? "mac" : "win" ) &&
+			c.isDisplayable() &&
+			(rootPane = SwingUtilities.getRootPane( c )) != null &&
+			(bounds = (Rectangle) rootPane.getClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_BOUNDS )) != null )
+		{
+			// On macOS, the client property is updated very late when toggling full screen,
+			// which results in "jumping" layout after full screen toggle finished.
+			// To avoid that, get up-to-date buttons bounds from macOS.
+			if( SystemInfo.isMacFullWindowContentSupported && FlatNativeMacLibrary.isLoaded() ) {
+				Rectangle r = FlatNativeMacLibrary.getWindowButtonsBounds( SwingUtilities.windowForComponent( c ) );
+				if( r != null )
+					bounds = r;
+			}
+
+			if( options.length() > 3 ) {
+				if( options.contains( "horizontal" ) )
+					return new Dimension( bounds.width, 0 );
+				if( options.contains( "vertical" ) )
+					return new Dimension( 0, bounds.height );
+			}
+
+			return bounds.getSize();
+		}
+
+		// default to 0,0
+		return new Dimension();
+	}
+
+	static void registerPlaceholder( JComponent c ) {
+		synchronized( placeholders ) {
+			if( indexOfPlaceholder( c ) < 0 )
+				placeholders.add( new WeakReference<>( c ) );
+		}
+	}
+
+	static void unregisterPlaceholder( JComponent c ) {
+		synchronized( placeholders ) {
+			int index = indexOfPlaceholder( c );
+			if( index >= 0 )
+				placeholders.remove( index );
+		}
+	}
+
+	private static int indexOfPlaceholder( JComponent c ) {
+		int size = placeholders.size();
+		for( int i = 0; i < size; i++ ) {
+			if( placeholders.get( i ).get() == c )
+				return i;
+		}
+		return -1;
+	}
+
+	static void revalidatePlaceholders( Component container ) {
+		synchronized( placeholders ) {
+			if( placeholders.isEmpty() )
+				return;
+
+			for( Iterator<WeakReference<JComponent>> it = placeholders.iterator(); it.hasNext(); ) {
+				WeakReference<JComponent> ref = it.next();
+				JComponent c = ref.get();
+
+				// remove already released placeholder
+				if( c == null ) {
+					it.remove();
+					continue;
+				}
+
+				// revalidate placeholder if is in given container
+				if( SwingUtilities.isDescendingFrom( c, container ) )
+					c.revalidate();
+			}
+		}
+	}
+
+	static ComponentListener macInstallListeners( JRootPane rootPane ) {
+		ComponentListener l = new ComponentAdapter() {
+			boolean lastFullScreen;
+
+			@Override
+			public void componentResized( ComponentEvent e ) {
+				Window window = SwingUtilities.windowForComponent( rootPane );
+				if( window == null )
+					return;
+
+				boolean fullScreen = FlatNativeMacLibrary.isLoaded() && FlatNativeMacLibrary.isWindowFullScreen( window );
+				if( fullScreen == lastFullScreen )
+					return;
+
+				lastFullScreen = fullScreen;
+				macUpdateFullWindowContentButtonsBoundsProperty( rootPane );
+			}
+		};
+
+		rootPane.addComponentListener( l );
+		return l;
+	}
+
+	static void macUninstallListeners( JRootPane rootPane, ComponentListener l ) {
+		if( l != null )
+			rootPane.removeComponentListener( l );
+	}
+
+	static void macUpdateFullWindowContentButtonsBoundsProperty( JRootPane rootPane ) {
+		if( !SystemInfo.isMacFullWindowContentSupported ||
+			!rootPane.isDisplayable() ||
+			!FlatClientProperties.clientPropertyBoolean( rootPane, "apple.awt.fullWindowContent", false ) )
+		  return;
+
+		Rectangle bounds = FlatNativeMacLibrary.isLoaded()
+			? FlatNativeMacLibrary.getWindowButtonsBounds( SwingUtilities.windowForComponent( rootPane ) )
+			: new Rectangle( 68, 28 ); // default size
+		rootPane.putClientProperty( FlatClientProperties.FULL_WINDOW_CONTENT_BUTTONS_BOUNDS, bounds );
+	}
+
+	static void debugPaint( Graphics g, JComponent c ) {
+		if( !UIManager.getBoolean( KEY_DEBUG_SHOW_PLACEHOLDERS ) )
+			return;
+
+		int width = c.getWidth() - 1;
+		int height = c.getHeight() - 1;
+		if( width <= 0 || height <= 0 )
+			return;
+
+		g.setColor( Color.red );
+		g.drawRect( 0, 0, width, height );
+
+		// draw diagonal cross
+		Object[] oldRenderingHints = FlatUIUtils.setRenderingHints( g );
+		g.drawLine( 0, 0, width, height );
+		g.drawLine( 0, height, width, 0 );
+		FlatUIUtils.resetRenderingHints( g, oldRenderingHints );
+	}
+}