Styling: basic support for "classes" (similar to CSS classes) using client property FlatLaf.styleClass

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

@@ -145,6 +145,38 @@ public interface FlatClientProperties
 	 */
 	String STYLE = "FlatLaf.style";
 
+	/**
+	 * Specifies the style class(es) of a component as String
+	 * or as {@link java.util.List}<String>.
+	 * <p>
+	 * The style rules must be defined in UI defaults either as strings (in CSS syntax)
+	 * or as {@link java.util.Map}&lt;String, Object&gt; (with binary values).
+	 * The key must be in syntax: {@code [style]type.styleClass}, where the type is optional.
+	 * E.g. in FlatLaf properties file:
+	 * <pre>{@code
+	 * [style]Button.primary = borderColor: #08f; background: #08f; foreground: #fff
+	 * [style].secondary = borderColor: #0f8; background: #0f8
+	 * }</pre>
+	 * or in Java code:
+	 * <pre>{@code
+	 * UIManager.put( "[style]Button.primary", "borderColor: #08f; background: #08f; foreground: #fff" );
+	 * UIManager.put( "[style].secondary", "borderColor: #0f8; background: #0f8" );
+	 * }</pre>
+	 * The rule "Button.primary" can be applied to buttons only.
+	 * The rule ".secondary" can be applied to any component.
+	 * <p>
+	 * To have similar behaviour as in CSS, first the rule without type is applied,
+	 * then the rule with type.
+	 * E.g. setting style class to "foo" on a {@code JButton} uses rules
+	 * from UI default keys "[style].foo" and "[style]Button.foo".
+	 * <p>
+	 * <strong>Components</strong> {@link javax.swing.JComponent}<br>
+	 * <strong>Value type</strong> {@link java.lang.String}, {@code String[]} or {@link java.util.List}&lt;String&gt;<br>
+	 *
+	 * @since 2
+	 */
+	String STYLE_CLASS = "FlatLaf.styleClass";
+
 	/**
 	 * Specifies minimum width of a component.
 	 * <p>

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

@@ -152,6 +152,7 @@ public class FlatButtonUI
 			: new FlatButtonUI( false );
 	}
 
+	/** @since 2 */
 	protected FlatButtonUI( boolean shared ) {
 		this.shared = shared;
 	}
@@ -160,7 +161,7 @@ public class FlatButtonUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( (AbstractButton) c, FlatStylingSupport.getStyle( c ) );
+		installStyle( (AbstractButton) c );
 	}
 
 	@Override
@@ -254,19 +255,29 @@ public class FlatButtonUI
 				break;
 
 			case STYLE:
-				Object style = e.getNewValue();
-				if( style != null && shared ) {
+			case STYLE_CLASS:
+				if( shared && FlatStylingSupport.hasStyleProperty( b ) ) {
 					// unshare component UI if necessary
 					// updateUI() invokes applyStyle() from installUI()
 					b.updateUI();
 				} else
-					applyStyle( b, style );
+					installStyle( b );
 				b.revalidate();
 				b.repaint();
 				break;
 		}
 	}
 
+	/** @since 2 */
+	protected void installStyle( AbstractButton b ) {
+		applyStyle( b, FlatStylingSupport.getResolvedStyle( b, getStyleType() ) );
+	}
+
+	/** @since 2 */
+	String getStyleType() {
+		return "Button";
+	}
+
 	/** @since 2 */
 	protected void applyStyle( AbstractButton b, Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style,

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

@@ -72,7 +72,7 @@ public class FlatCheckBoxMenuItemUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( menuItem ) );
+		installStyle();
 	}
 
 	@Override
@@ -98,7 +98,12 @@ public class FlatCheckBoxMenuItemUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::applyStyle, super.createPropertyChangeListener( c ) );
+		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+	}
+
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( menuItem, "CheckBoxMenuItem" ) );
 	}
 
 	/** @since 2 */

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

@@ -57,4 +57,10 @@ public class FlatCheckBoxUI
 	public String getPropertyPrefix() {
 		return "CheckBox.";
 	}
+
+	/** @since 2 */
+	@Override
+	String getStyleType() {
+		return "CheckBox";
+	}
 }

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

@@ -16,6 +16,7 @@
 
 package com.formdev.flatlaf.ui;
 
+import static com.formdev.flatlaf.FlatClientProperties.*;
 import static com.formdev.flatlaf.util.UIScale.scale;
 import static com.formdev.flatlaf.util.UIScale.unscale;
 import java.awt.Color;
@@ -69,7 +70,6 @@ import javax.swing.plaf.basic.BasicComboBoxUI;
 import javax.swing.plaf.basic.BasicComboPopup;
 import javax.swing.plaf.basic.ComboPopup;
 import javax.swing.text.JTextComponent;
-import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.util.SystemInfo;
@@ -155,7 +155,7 @@ public class FlatComboBoxUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( comboBox ) );
+		installStyle();
 	}
 
 	@Override
@@ -341,16 +341,28 @@ public class FlatComboBoxUI
 			} else if( editor != null && source == comboBox && propertyName == "componentOrientation" ) {
 				ComponentOrientation o = (ComponentOrientation) e.getNewValue();
 				editor.applyComponentOrientation( o );
-			} else if( editor != null && FlatClientProperties.PLACEHOLDER_TEXT.equals( propertyName ) )
-				editor.repaint();
-			else if( FlatClientProperties.COMPONENT_ROUND_RECT.equals( propertyName ) )
-				comboBox.repaint();
-			else if( FlatClientProperties.MINIMUM_WIDTH.equals( propertyName ) )
-				comboBox.revalidate();
-			else if( FlatClientProperties.STYLE.equals( propertyName ) ) {
-				applyStyle( e.getNewValue() );
-				comboBox.revalidate();
-				comboBox.repaint();
+			} else {
+				switch( propertyName ) {
+					case PLACEHOLDER_TEXT:
+						if( editor != null )
+							editor.repaint();
+						break;
+
+					case COMPONENT_ROUND_RECT:
+						comboBox.repaint();
+						break;
+
+					case MINIMUM_WIDTH:
+						comboBox.revalidate();
+						break;
+
+					case STYLE:
+					case STYLE_CLASS:
+						installStyle();
+						comboBox.revalidate();
+						comboBox.repaint();
+						break;
+				}
 			}
 		};
 	}
@@ -419,7 +431,7 @@ public class FlatComboBoxUI
 				unscale( Math.max( scale( padding.right ) - insets.right, 0 ) )
 			);
 		}
-		textField.putClientProperty( FlatClientProperties.TEXT_FIELD_PADDING, pad );
+		textField.putClientProperty( TEXT_FIELD_PADDING, pad );
 	}
 
 	private void updateEditorColors() {
@@ -438,6 +450,11 @@ public class FlatComboBoxUI
 		return new FlatComboBoxButton();
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( comboBox, "ComboBox" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		Insets oldPadding = padding;

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

@@ -25,7 +25,6 @@ import java.awt.Insets;
 import java.awt.event.FocusListener;
 import java.beans.PropertyChangeEvent;
 import java.util.Map;
-import java.util.function.Consumer;
 import javax.swing.JComponent;
 import javax.swing.JEditorPane;
 import javax.swing.UIManager;
@@ -91,7 +90,7 @@ public class FlatEditorPaneUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -155,23 +154,29 @@ public class FlatEditorPaneUI
 			updateBackground();
 
 		super.propertyChange( e );
-		propertyChange( getComponent(), e, this::applyStyle );
+		propertyChange( getComponent(), e, this::installStyle );
 	}
 
-	static void propertyChange( JTextComponent c, PropertyChangeEvent e, Consumer<Object> applyStyle ) {
+	static void propertyChange( JTextComponent c, PropertyChangeEvent e, Runnable installStyle ) {
 		switch( e.getPropertyName() ) {
 			case FlatClientProperties.MINIMUM_WIDTH:
 				c.revalidate();
 				break;
 
 			case FlatClientProperties.STYLE:
-				applyStyle.accept( e.getNewValue() );
+			case FlatClientProperties.STYLE_CLASS:
+				installStyle.run();
 				c.revalidate();
 				c.repaint();
 				break;
 		}
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( getComponent(), "EditorPane" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldDisabledBackground = disabledBackground;

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

@@ -60,4 +60,10 @@ public class FlatFormattedTextFieldUI
 	protected String getPropertyPrefix() {
 		return "FormattedTextField";
 	}
+
+	/** @since 2 */
+	@Override
+	String getStyleType() {
+		return "FormattedTextField";
+	}
 }

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

@@ -116,7 +116,7 @@ public class FlatInternalFrameUI
 
 		windowResizer = createWindowResizer();
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -148,10 +148,15 @@ public class FlatInternalFrameUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener() {
-		return FlatStylingSupport.createPropertyChangeListener( frame, this::applyStyle,
+		return FlatStylingSupport.createPropertyChangeListener( frame, this::installStyle,
 			super.createPropertyChangeListener() );
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( frame, "InternalFrame" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -81,7 +81,7 @@ public class FlatLabelUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( (JLabel) c, FlatStylingSupport.getStyle( c ) );
+		installStyle( (JLabel) c );
 	}
 
 	@Override
@@ -117,21 +117,25 @@ public class FlatLabelUI
 		if( name == "text" || name == "font" || name == "foreground" ) {
 			JLabel label = (JLabel) e.getSource();
 			updateHTMLRenderer( label, label.getText(), true );
-		} else if( name.equals( FlatClientProperties.STYLE ) ) {
+		} else if( name.equals( FlatClientProperties.STYLE ) || name.equals( FlatClientProperties.STYLE_CLASS ) ) {
 			JLabel label = (JLabel) e.getSource();
-			Object style = e.getNewValue();
-			if( style != null && shared ) {
+			if( shared && FlatStylingSupport.hasStyleProperty( label ) ) {
 				// unshare component UI if necessary
 				// updateUI() invokes applyStyle() from installUI()
 				label.updateUI();
 			} else
-				applyStyle( label, style );
+				installStyle( label );
 			label.revalidate();
 			label.repaint();
 		} else
 			super.propertyChange( e );
 	}
 
+	/** @since 2 */
+	protected void installStyle( JLabel c ) {
+		applyStyle( c, FlatStylingSupport.getResolvedStyle( c, "Label" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( JLabel c, Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style,

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

@@ -91,7 +91,7 @@ public class FlatListUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -151,7 +151,8 @@ public class FlatListUI
 					break;
 
 				case FlatClientProperties.STYLE:
-					applyStyle( e.getNewValue() );
+				case FlatClientProperties.STYLE_CLASS:
+					installStyle();
 					list.revalidate();
 					list.repaint();
 					break;
@@ -159,6 +160,11 @@ public class FlatListUI
 		};
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( list, "List" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		Color oldSelectionBackground = selectionBackground;

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

@@ -39,7 +39,6 @@ import javax.swing.plaf.ActionMapUIResource;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.UIResource;
 import javax.swing.plaf.basic.BasicMenuBarUI;
-import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.FlatLaf;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
@@ -91,7 +90,7 @@ public class FlatMenuBarUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -113,16 +112,15 @@ public class FlatMenuBarUI
 	protected void installListeners() {
 		super.installListeners();
 
-		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener(
-			menuBar, this::applyStyle, null );
-		menuBar.addPropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener( menuBar, this::installStyle, null );
+		menuBar.addPropertyChangeListener( propertyChangeListener );
 	}
 
 	@Override
 	protected void uninstallListeners() {
 		super.uninstallListeners();
 
-		menuBar.removePropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		menuBar.removePropertyChangeListener( propertyChangeListener );
 		propertyChangeListener = null;
 	}
 
@@ -138,6 +136,11 @@ public class FlatMenuBarUI
 		map.put( "takeFocus", new TakeFocus() );
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( menuBar, "MenuBar" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -73,7 +73,7 @@ public class FlatMenuItemUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( menuItem ) );
+		installStyle();
 	}
 
 	@Override
@@ -99,7 +99,12 @@ public class FlatMenuItemUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::applyStyle, super.createPropertyChangeListener( c ) );
+		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+	}
+
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( menuItem, "MenuItem" ) );
 	}
 
 	/** @since 2 */

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

@@ -92,7 +92,7 @@ public class FlatMenuUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( menuItem ) );
+		installStyle();
 	}
 
 	@Override
@@ -145,7 +145,12 @@ public class FlatMenuUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::applyStyle, super.createPropertyChangeListener( c ) );
+		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+	}
+
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( menuItem, "Menu" ) );
 	}
 
 	/** @since 2 */

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

@@ -162,6 +162,12 @@ public class FlatPasswordFieldUI
 		}
 	}
 
+	/** @since 2 */
+	@Override
+	String getStyleType() {
+		return "PasswordField";
+	}
+
 	/** @since 2 */
 	@Override
 	protected Object applyStyleProperty( String key, Object value ) {

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

@@ -53,4 +53,10 @@ public class FlatPopupMenuSeparatorUI
 	protected String getPropertyPrefix() {
 		return "PopupMenuSeparator";
 	}
+
+	/** @since 2 */
+	@Override
+	String getStyleType() {
+		return "PopupMenuSeparator";
+	}
 }

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

@@ -22,7 +22,6 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import javax.swing.JComponent;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicPopupMenuUI;
-import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 
 /**
@@ -53,7 +52,7 @@ public class FlatPopupMenuUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -68,18 +67,23 @@ public class FlatPopupMenuUI
 	protected void installListeners() {
 		super.installListeners();
 
-		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener( popupMenu, this::applyStyle, null );
-		popupMenu.addPropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener( popupMenu, this::installStyle, null );
+		popupMenu.addPropertyChangeListener( propertyChangeListener );
 	}
 
 	@Override
 	protected void uninstallListeners() {
 		super.uninstallListeners();
 
-		popupMenu.removePropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		popupMenu.removePropertyChangeListener( propertyChangeListener );
 		propertyChangeListener = null;
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( popupMenu, "PopupMenu" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -78,7 +78,7 @@ public class FlatProgressBarUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( progressBar ) );
+		installStyle();
 	}
 
 	@Override
@@ -112,7 +112,8 @@ public class FlatProgressBarUI
 					break;
 
 				case STYLE:
-					applyStyle( e.getNewValue() );
+				case STYLE_CLASS:
+					installStyle();
 					progressBar.revalidate();
 					progressBar.repaint();
 					break;
@@ -129,6 +130,11 @@ public class FlatProgressBarUI
 		propertyChangeListener = null;
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( progressBar, "ProgressBar" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -72,7 +72,7 @@ public class FlatRadioButtonMenuItemUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( menuItem ) );
+		installStyle();
 	}
 
 	@Override
@@ -98,7 +98,12 @@ public class FlatRadioButtonMenuItemUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JComponent c ) {
-		return FlatStylingSupport.createPropertyChangeListener( c, this::applyStyle, super.createPropertyChangeListener( c ) );
+		return FlatStylingSupport.createPropertyChangeListener( c, this::installStyle, super.createPropertyChangeListener( c ) );
+	}
+
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( menuItem, "RadioButtonMenuItem" ) );
 	}
 
 	/** @since 2 */

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

@@ -90,7 +90,7 @@ public class FlatRadioButtonUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( (AbstractButton) c, FlatStylingSupport.getStyle( c ) );
+		installStyle( (AbstractButton) c );
 	}
 
 	@Override
@@ -134,19 +134,29 @@ public class FlatRadioButtonUI
 	protected void propertyChange( AbstractButton b, PropertyChangeEvent e ) {
 		switch( e.getPropertyName() ) {
 			case FlatClientProperties.STYLE:
-				Object style = e.getNewValue();
-				if( style != null && shared ) {
+			case FlatClientProperties.STYLE_CLASS:
+				if( shared && FlatStylingSupport.hasStyleProperty( b ) ) {
 					// unshare component UI if necessary
 					// updateUI() invokes applyStyle() from installUI()
 					b.updateUI();
 				} else
-					applyStyle( b, style );
+					installStyle( b );
 				b.revalidate();
 				b.repaint();
 				break;
 		}
 	}
 
+	/** @since 2 */
+	protected void installStyle( AbstractButton b ) {
+		applyStyle( b, FlatStylingSupport.getResolvedStyle( b, getStyleType() ) );
+	}
+
+	/** @since 2 */
+	String getStyleType() {
+		return "RadioButton";
+	}
+
 	/** @since 2 */
 	protected void applyStyle( AbstractButton b, Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style,

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

@@ -115,7 +115,7 @@ public class FlatScrollBarUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -199,7 +199,8 @@ public class FlatScrollBarUI
 					break;
 
 				case FlatClientProperties.STYLE:
-					applyStyle( e.getNewValue() );
+				case FlatClientProperties.STYLE_CLASS:
+					installStyle();
 					scrollbar.revalidate();
 					scrollbar.repaint();
 					break;
@@ -220,6 +221,11 @@ public class FlatScrollBarUI
 		};
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( scrollbar, "ScrollBar" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -87,7 +87,7 @@ public class FlatScrollPaneUI
 		int focusWidth = UIManager.getInt( "Component.focusWidth" );
 		LookAndFeel.installProperty( c, "opaque", focusWidth == 0 );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 
 		MigLayoutVisualPadding.install( scrollpane );
 	}
@@ -287,7 +287,8 @@ public class FlatScrollPaneUI
 					break;
 
 				case FlatClientProperties.STYLE:
-					applyStyle( e.getNewValue() );
+				case FlatClientProperties.STYLE_CLASS:
+					installStyle();
 					scrollpane.revalidate();
 					scrollpane.repaint();
 					break;
@@ -301,6 +302,11 @@ public class FlatScrollPaneUI
 		return handler;
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( scrollpane, "ScrollPane" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -28,7 +28,6 @@ import javax.swing.JSeparator;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 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;
 
@@ -80,7 +79,7 @@ public class FlatSeparatorUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( (JSeparator) c, FlatStylingSupport.getStyle( c ) );
+		installStyle( (JSeparator) c );
 	}
 
 	@Override
@@ -110,29 +109,39 @@ public class FlatSeparatorUI
 		super.installListeners( s );
 
 		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener(
-			s, style -> applyStyle( s, this, style ), null );
-		s.addPropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+			s, () -> stylePropertyChange( s ), null );
+		s.addPropertyChangeListener( propertyChangeListener );
 	}
 
 	@Override
 	protected void uninstallListeners( JSeparator s ) {
 		super.uninstallListeners( s );
 
-		s.removePropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		s.removePropertyChangeListener( propertyChangeListener );
 		propertyChangeListener = null;
 	}
 
-	private static void applyStyle( JSeparator s, FlatSeparatorUI ui, Object style ) {
-		if( style != null && ui.shared ) {
+	private void stylePropertyChange( JSeparator s ) {
+		if( shared && FlatStylingSupport.hasStyleProperty( s ) ) {
 			// unshare component UI if necessary
 			// updateUI() invokes applyStyle() from installUI()
 			s.updateUI();
 		} else
-			ui.applyStyle( s, style );
+			installStyle( s );
 		s.revalidate();
 		s.repaint();
 	}
 
+	/** @since 2 */
+	protected void installStyle( JSeparator s ) {
+		applyStyle( s, FlatStylingSupport.getResolvedStyle( s, getStyleType() ) );
+	}
+
+	/** @since 2 */
+	String getStyleType() {
+		return "Separator";
+	}
+
 	/** @since 2 */
 	protected void applyStyle( JSeparator s, Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style,

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

@@ -121,7 +121,7 @@ public class FlatSliderUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( slider ) );
+		installStyle();
 	}
 
 	@Override
@@ -188,10 +188,15 @@ public class FlatSliderUI
 
 	@Override
 	protected PropertyChangeListener createPropertyChangeListener( JSlider slider ) {
-		return FlatStylingSupport.createPropertyChangeListener( slider, this::applyStyle,
+		return FlatStylingSupport.createPropertyChangeListener( slider, this::installStyle,
 			super.createPropertyChangeListener( slider ) );
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( slider, "Slider" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -114,7 +114,7 @@ public class FlatSpinnerUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( spinner ) );
+		installStyle();
 	}
 
 	@Override
@@ -190,6 +190,11 @@ public class FlatSpinnerUI
 		return handler;
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( spinner, "Spinner" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );
@@ -530,7 +535,8 @@ public class FlatSpinnerUI
 					break;
 
 				case FlatClientProperties.STYLE:
-					applyStyle( e.getNewValue() );
+				case FlatClientProperties.STYLE_CLASS:
+					installStyle();
 					spinner.revalidate();
 					spinner.repaint();
 					break;

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

@@ -34,7 +34,6 @@ import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.basic.BasicSplitPaneDivider;
 import javax.swing.plaf.basic.BasicSplitPaneUI;
-import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.ui.FlatStylingSupport.UnknownStyleException;
@@ -90,7 +89,7 @@ public class FlatSplitPaneUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( splitPane ) );
+		installStyle();
 	}
 
 	@Override
@@ -121,15 +120,15 @@ public class FlatSplitPaneUI
 	protected void installListeners() {
 		super.installListeners();
 
-		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener( splitPane, this::applyStyle, null );
-		splitPane.addPropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener( splitPane, this::installStyle, null );
+		splitPane.addPropertyChangeListener( propertyChangeListener );
 	}
 
 	@Override
 	protected void uninstallListeners() {
 		super.uninstallListeners();
 
-		splitPane.removePropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		splitPane.removePropertyChangeListener( propertyChangeListener );
 		propertyChangeListener = null;
 	}
 
@@ -138,6 +137,11 @@ public class FlatSplitPaneUI
 		return new FlatSplitPaneDivider( this );
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( splitPane, "SplitPane" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -26,10 +26,10 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.BiFunction;
-import java.util.function.Consumer;
 import java.util.function.Predicate;
 import javax.swing.Icon;
 import javax.swing.JComponent;
@@ -73,6 +73,150 @@ public class FlatStylingSupport
 		Map<String, Class<?>> getStyleableInfos();
 	}
 
+
+	/**
+	 * Returns the style specified in client property {@link FlatClientProperties#STYLE}.
+	 */
+	public static Object getStyle( JComponent c ) {
+		return c.getClientProperty( FlatClientProperties.STYLE );
+	}
+
+	/**
+	 * Returns the style class(es) specified in client property {@link FlatClientProperties#STYLE_CLASS}.
+	 */
+	public static Object getStyleClass( JComponent c ) {
+		return c.getClientProperty( FlatClientProperties.STYLE_CLASS );
+	}
+
+	static boolean hasStyleProperty( JComponent c ) {
+		return getStyle( c ) != null || getStyleClass( c ) != null;
+	}
+
+	public static Object getResolvedStyle( JComponent c, String type ) {
+		Object style = getStyle( c );
+		Object styleClass = getStyleClass( c );
+		Object styleForClasses = getStyleForClasses( styleClass, type );
+		return joinStyles( styleForClasses, style );
+	}
+
+	/**
+	 * Returns the styles for the given style class(es) and the given type.
+	 * <p>
+	 * The style rules must be defined in UI defaults either as strings (in CSS syntax)
+	 * or as {@link java.util.Map}&lt;String, Object&gt; (with binary values).
+	 * The key must be in syntax: {@code [style]type.styleClass}, where the type is optional.
+	 * E.g. in FlatLaf properties file:
+	 * <pre>{@code
+	 * [style]Button.primary = borderColor: #08f; background: #08f; foreground: #fff
+	 * [style].secondary = borderColor: #0f8; background: #0f8
+	 * }</pre>
+	 * or in Java code:
+	 * <pre>{@code
+	 * UIManager.put( "[style]Button.primary", "borderColor: #08f; background: #08f; foreground: #fff" );
+	 * UIManager.put( "[style].secondary", "borderColor: #0f8; background: #0f8" );
+	 * }</pre>
+	 * The rule "Button.primary" can be applied to buttons only.
+	 * The rule ".secondary" can be applied to any component.
+	 * <p>
+	 * To have similar behaviour as in CSS, this method first gets the rule without type,
+	 * then the rule with type and concatenates both rules.
+	 * E.g. invoking this method with parameters styleClass="foo" and type="Button" does following:
+	 * <pre>{@code
+	 * return joinStyles(
+	 *     UIManager.get( "[style].foo" ),
+	 *     UIManager.get( "[style]Button.foo" ) );
+	 * }</pre>
+	 *
+	 * @param styleClass the style class(es) either as string (single class)
+	 *                   or as {@code String[]} or {@link java.util.List}&lt;String&gt; (multiple classes)
+	 * @param type the type of the component
+	 * @return the styles
+	 */
+	public static Object getStyleForClasses( Object styleClass, String type ) {
+		if( styleClass == null )
+			return null;
+
+		if( styleClass instanceof String )
+			return getStyleForClass( (String) styleClass, type );
+		else if( styleClass instanceof String[] ) {
+			Object style = null;
+			for( String cls : (String[]) styleClass )
+				style = joinStyles( style, getStyleForClass( cls, type ) );
+			return style;
+		} else if( styleClass instanceof List<?> ) {
+			Object style = null;
+			for( Object cls : (List<?>) styleClass )
+				style = joinStyles( style, getStyleForClass( (String) cls, type ) );
+			return style;
+		} else
+			return null;
+	}
+
+	private static Object getStyleForClass( String styleClass, String type ) {
+		return joinStyles(
+			UIManager.get( "[style]." + styleClass ),
+			UIManager.get( "[style]" + type + '.' + styleClass ) );
+	}
+
+	/**
+	 * Joins two styles. They can be either strings (in CSS syntax)
+	 * or {@link java.util.Map}&lt;String, Object&gt; (with binary values).
+	 * <p>
+	 * If both styles are strings, then a joined string is returned.
+	 * If both styles are maps, then a joined map is returned.
+	 * If one style is a map and the other style a string, then the string
+	 * is parsed (using {@link #parse(String)}) to a map and a joined map is returned.
+	 *
+	 * @param style1 first style as string or map, or {@code null}
+	 * @param style2 second style as string or map, or {@code null}
+	 * @return new joined style
+	 */
+	@SuppressWarnings( "unchecked" )
+	public static Object joinStyles( Object style1, Object style2 ) {
+		if( style1 == null )
+			return style2;
+		if( style2 == null )
+			return style1;
+
+		// join two strings
+		if( style1 instanceof String && style2 instanceof String )
+			return style1 + "; " + style2;
+
+		// convert first style to map
+		Map<String, Object> map1 = (style1 instanceof String)
+			? parse( (String) style1 )
+			: (Map<String, Object>) style1;
+		if( map1 == null )
+			return style2;
+
+		// convert second style to map
+		Map<String, Object> map2 = (style2 instanceof String)
+			? parse( (String) style2 )
+			: (Map<String, Object>) style2;
+		if( map2 == null )
+			return style1;
+
+		// join two maps
+		Map<String, Object> map = new HashMap<>( map1 );
+		map.putAll( map2 );
+		return map;
+	}
+
+	/**
+	 * Concatenates two styles in CSS syntax.
+	 *
+	 * @param style1 first style, or {@code null}
+	 * @param style2 second style, or {@code null}
+	 * @return concatenation of the two styles separated by a semicolon
+	 */
+	public static String concatStyles( String style1, String style2 ) {
+		if( style1 == null )
+			return style2;
+		if( style2 == null )
+			return style1;
+		return style1 + "; " + style2;
+	}
+
 	/**
 	 * Parses styles in CSS syntax ("key1: value1; key2: value2; ..."),
 	 * converts the value strings into binary and invokes the given function
@@ -408,21 +552,20 @@ public class FlatStylingSupport
 		}
 	}
 
-	public static Object getStyle( JComponent c ) {
-		return c.getClientProperty( FlatClientProperties.STYLE );
-	}
-
 	static PropertyChangeListener createPropertyChangeListener( JComponent c,
-		Consumer<Object> applyStyle, PropertyChangeListener superListener )
+		Runnable installStyle, PropertyChangeListener superListener )
 	{
 		return e -> {
 			if( superListener != null )
 				superListener.propertyChange( e );
 
-			if( FlatClientProperties.STYLE.equals( e.getPropertyName() ) ) {
-				applyStyle.accept( e.getNewValue() );
-				c.revalidate();
-				c.repaint();
+			switch( e.getPropertyName() ) {
+				case FlatClientProperties.STYLE:
+				case FlatClientProperties.STYLE_CLASS:
+					installStyle.run();
+					c.revalidate();
+					c.repaint();
+					break;
 			}
 		};
 	}

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

@@ -269,7 +269,7 @@ public class FlatTabbedPaneUI
 
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -572,6 +572,11 @@ public class FlatTabbedPaneUI
 		return new FlatScrollableTabButton( direction );
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( tabPane, "TabbedPane" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );
@@ -2439,7 +2444,8 @@ public class FlatTabbedPaneUI
 					break;
 
 				case STYLE:
-					applyStyle( e.getNewValue() );
+				case STYLE_CLASS:
+					installStyle();
 					tabPane.revalidate();
 					tabPane.repaint();
 					break;

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

@@ -41,7 +41,6 @@ import javax.swing.plaf.UIResource;
 import javax.swing.plaf.basic.BasicTableHeaderUI;
 import javax.swing.table.TableCellRenderer;
 import javax.swing.table.TableColumnModel;
-import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.ui.FlatStylingSupport.Styleable;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.util.UIScale;
@@ -104,7 +103,7 @@ public class FlatTableHeaderUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -129,18 +128,23 @@ public class FlatTableHeaderUI
 	protected void installListeners() {
 		super.installListeners();
 
-		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener( header, this::applyStyle, null );
-		header.addPropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener( header, this::installStyle, null );
+		header.addPropertyChangeListener( propertyChangeListener );
 	}
 
 	@Override
 	protected void uninstallListeners() {
 		super.uninstallListeners();
 
-		header.removePropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		header.removePropertyChangeListener( propertyChangeListener );
 		propertyChangeListener = null;
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( header, "TableHeader" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -126,7 +126,7 @@ public class FlatTableUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -197,7 +197,8 @@ public class FlatTableUI
 					break;
 
 				case FlatClientProperties.STYLE:
-					applyStyle( e.getNewValue() );
+				case FlatClientProperties.STYLE_CLASS:
+					installStyle();
 					table.revalidate();
 					table.repaint();
 					break;
@@ -235,6 +236,11 @@ public class FlatTableUI
 		};
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( table, "Table" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		Color oldSelectionBackground = selectionBackground;

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

@@ -86,7 +86,7 @@ public class FlatTextAreaUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -143,7 +143,12 @@ public class FlatTextAreaUI
 			updateBackground();
 
 		super.propertyChange( e );
-		FlatEditorPaneUI.propertyChange( getComponent(), e, this::applyStyle );
+		FlatEditorPaneUI.propertyChange( getComponent(), e, this::installStyle );
+	}
+
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( getComponent(), "TextArea" ) );
 	}
 
 	/** @since 2 */

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

@@ -114,7 +114,7 @@ public class FlatTextFieldUI
 		leadingIcon = clientProperty( c, TEXT_FIELD_LEADING_ICON, null, Icon.class );
 		trailingIcon = clientProperty( c, TEXT_FIELD_TRAILING_ICON, null, Icon.class );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -209,7 +209,8 @@ public class FlatTextFieldUI
 				break;
 
 			case STYLE:
-				applyStyle( e.getNewValue() );
+			case STYLE_CLASS:
+				installStyle();
 				c.revalidate();
 				c.repaint();
 				break;
@@ -226,6 +227,16 @@ public class FlatTextFieldUI
 		}
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( getComponent(), getStyleType() ) );
+	}
+
+	/** @since 2 */
+	String getStyleType() {
+		return "TextField";
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldDisabledBackground = disabledBackground;

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

@@ -87,7 +87,7 @@ public class FlatTextPaneUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -151,7 +151,12 @@ public class FlatTextPaneUI
 			updateBackground();
 
 		super.propertyChange( e );
-		FlatEditorPaneUI.propertyChange( getComponent(), e, this::applyStyle );
+		FlatEditorPaneUI.propertyChange( getComponent(), e, this::installStyle );
+	}
+
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( getComponent(), "TextPane" ) );
 	}
 
 	/** @since 2 */

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

@@ -96,6 +96,11 @@ public class FlatToggleButtonUI
 		super( shared );
 	}
 
+	@Override
+	String getStyleType() {
+		return "ToggleButton";
+	}
+
 	@Override
 	protected String getPropertyPrefix() {
 		return "ToggleButton.";

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

@@ -31,7 +31,6 @@ import javax.swing.SwingConstants;
 import javax.swing.UIManager;
 import javax.swing.plaf.ComponentUI;
 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;
 
@@ -74,7 +73,7 @@ public class FlatToolBarSeparatorUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle( (JSeparator) c );
 	}
 
 	@Override
@@ -106,29 +105,34 @@ public class FlatToolBarSeparatorUI
 		super.installListeners( s );
 
 		propertyChangeListener = FlatStylingSupport.createPropertyChangeListener(
-			s, style -> applyStyle( s, this, style ), null );
-		s.addPropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+			s, () -> stylePropertyChange( s ), null );
+		s.addPropertyChangeListener( propertyChangeListener );
 	}
 
 	@Override
 	protected void uninstallListeners( JSeparator s ) {
 		super.uninstallListeners( s );
 
-		s.removePropertyChangeListener( FlatClientProperties.STYLE, propertyChangeListener );
+		s.removePropertyChangeListener( propertyChangeListener );
 		propertyChangeListener = null;
 	}
 
-	private static void applyStyle( JSeparator s, FlatToolBarSeparatorUI ui, Object style ) {
-		if( style != null && ui.shared ) {
+	private void stylePropertyChange( JSeparator s ) {
+		if( shared && FlatStylingSupport.hasStyleProperty( s ) ) {
 			// unshare component UI if necessary
 			// updateUI() invokes applyStyle() from installUI()
 			s.updateUI();
 		} else
-			ui.applyStyle( style );
+			installStyle( s );
 		s.revalidate();
 		s.repaint();
 	}
 
+	/** @since 2 */
+	protected void installStyle( JSeparator s ) {
+		applyStyle( FlatStylingSupport.getResolvedStyle( s, "ToolBarSeparator" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -83,7 +83,7 @@ public class FlatToolBarUI
 		if( !focusableButtons )
 			setButtonsFocusable( false );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -133,7 +133,12 @@ public class FlatToolBarUI
 
 	@Override
 	protected PropertyChangeListener createPropertyListener() {
-		return FlatStylingSupport.createPropertyChangeListener( toolBar, this::applyStyle, super.createPropertyListener() );
+		return FlatStylingSupport.createPropertyChangeListener( toolBar, this::installStyle, super.createPropertyListener() );
+	}
+
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( toolBar, "ToolBar" ) );
 	}
 
 	/** @since 2 */

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

@@ -156,7 +156,7 @@ public class FlatTreeUI
 	public void installUI( JComponent c ) {
 		super.installUI( c );
 
-		applyStyle( FlatStylingSupport.getStyle( c ) );
+		installStyle();
 	}
 
 	@Override
@@ -271,7 +271,8 @@ public class FlatTreeUI
 						break;
 
 					case STYLE:
-						applyStyle( e.getNewValue() );
+					case STYLE_CLASS:
+						installStyle();
 						tree.revalidate();
 						tree.repaint();
 						break;
@@ -309,6 +310,11 @@ public class FlatTreeUI
 		return bounds;
 	}
 
+	/** @since 2 */
+	protected void installStyle() {
+		applyStyle( FlatStylingSupport.getResolvedStyle( tree, "Tree" ) );
+	}
+
 	/** @since 2 */
 	protected void applyStyle( Object style ) {
 		oldStyleValues = FlatStylingSupport.parseAndApply( oldStyleValues, style, this::applyStyleProperty );

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

@@ -370,14 +370,16 @@ public class FlatUIUtils
 	 * <li>an (optional) component border
 	 * <li>the (optional) component background
 	 * </ul>
+	 * <p>
+	 *
 	 * Each part is painted only if the corresponding part color is not {@code null}.
 	 * The parts are painted in this order:
-	 * <p>
 	 * <ol>
 	 * <li>background
 	 * <li>focus border
 	 * <li>border
 	 * </ol>
+	 * <p>
 	 *
 	 * <strong>Background</strong>:
 	 * The bounds of the filled round rectangle are
@@ -939,7 +941,7 @@ debug*/
 	 * with other components. This is only possible if it does not have styles.
 	 */
 	public static boolean canUseSharedUI( JComponent c ) {
-		return FlatStylingSupport.getStyle( c ) == null;
+		return !FlatStylingSupport.hasStyleProperty( c );
 	}
 
 	//---- class RepaintFocusListener -----------------------------------------

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

@@ -81,7 +81,7 @@ public class MigLayoutVisualPadding
 				return new Insets( focusWidth, focusWidth, focusWidth, focusWidth );
 			} else
 				return null;
-		}, "border", FlatClientProperties.STYLE );
+		}, "border", FlatClientProperties.STYLE, FlatClientProperties.STYLE_CLASS );
 	}
 
 	/**
@@ -100,7 +100,7 @@ public class MigLayoutVisualPadding
 		c.addPropertyChangeListener( (FlatMigListener) e -> {
 			String propertyName = e.getPropertyName();
 			for( String name : propertyNames ) {
-				if( name == propertyName ) {
+				if( name.equals( propertyName ) ) {
 					setVisualPadding( c, getPaddingFunction.apply( c ) );
 					break;
 				}