release 1.6.5

- oversized text if system font is "Inter" (issue #427)
- missing text if system font is "Cantarell" (on Fedora)

.github/workflows/ci.yml

@@ -34,6 +34,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - uses: gradle/wrapper-validation-action@v1
+        if: matrix.java == '1.8'
 
       - name: Setup Java ${{ matrix.java }}
         uses: actions/setup-java@v1
@@ -72,7 +73,7 @@ jobs:
     needs: build
     if: |
       github.event_name == 'push' &&
-      github.ref == 'refs/heads/main' &&
+      (github.ref == 'refs/heads/main' || startsWith( github.ref, 'refs/heads/develop-' )) &&
       github.repository == 'JFormDesigner/FlatLaf'
 
     steps:

CHANGELOG.md

@@ -1,6 +1,64 @@
 FlatLaf Change Log
 ==================
 
+## 1.6.5
+
+#### Fixed bugs
+
+- Linux: Fixed font problems when running on Oracle Java (OpenJDK is not
+  affected):
+  - oversized text if system font is "Inter" (issue #427)
+  - missing text if system font is "Cantarell" (on Fedora)
+- MenuItem: Changed accelerator delimiter from `-` to `+`. (Windows and Linux).
+- ComboBox: Fixed occasional `StackOverflowError` when modifying combo box not
+  on AWT thread. (issue #432)
+- macOS: Fixed `NullPointerException` when using AWT component
+  `java.awt.Choice`. (issue #439)
+- Native window decorations: Do not exit application with `UnsatisfiedLinkError`
+  in case that FlatLaf DLL cannot be executed because of restrictions on
+  temporary directory. Instead, continue with default window decorations. (issue
+  #436)
+
+
+## 1.6.4
+
+#### Fixed bugs
+
+- ComboBox: Fixed regression in FlatLaf 1.6.3 that makes selected item invisible
+  in popup list if `DefaultListCellRenderer` is used as renderer. If using
+  default renderer, it works. (issue #426)
+
+
+## 1.6.3
+
+#### Fixed bugs
+
+- ComboBox (not editable): Fixed regression in FlatLaf 1.6.2 that may display
+  text in non-editable combo boxes in bold. (issue #423)
+- Tree: Fixed editing cell issue with custom cell renderer and cell editor that
+  use same component for rendering and editing. (issue #385)
+
+
+## 1.6.2
+
+#### Fixed bugs
+
+- ComboBox (not editable): Fixed background painted outside of border if round
+  edges are enabled (client property `JComponent.roundRect` is `true`). (similar
+  to issue #382; regression since fixing #330 in FlatLaf 1.4)
+- ComboBox: Fixed `NullPointerException`, which may occur under special
+  circumstances. (issue #408)
+- Table: Do not select text in cell editor when it gets focus (when
+  `JTable.surrendersFocusOnKeystroke` is `true`) and
+  `TextComponent.selectAllOnFocusPolicy` is `once` (the default) or `always`.
+  (issue #395)
+- Linux: Fixed NPE when using `java.awt.TrayIcon`. (issue #405)
+- FileChooser: Workaround for crash on Windows with Java 17 32-bit (disabled
+  Windows icons). Java 17 64-bit is not affected. (issue #403)
+- Native window decorations: Fixed layout loop, which may occur under special
+  circumstances and slows down the application. (issue #420)
+
+
 ## 1.6.1
 
 #### Fixed bugs
@@ -33,7 +91,7 @@ FlatLaf Change Log
 - ComboBox (editable): Fixed wrong border of internal text field under special
   circumstances.
 - Spinner: Fixed painting of border corners on left side. (issue #382;
-  regression since FlatLaf 1.4)
+  regression since fixing #330 in FlatLaf 1.4)
 - TableHeader: Do not show resize cursor for last column if resizing last column
   is not possible because auto resize mode of table is not off. (issue #332)
 - TableHeader: Fixed missing trailing vertical separator line if used in upper

build.gradle.kts

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-val releaseVersion = "1.6.1"
-val developmentVersion = "2.0-SNAPSHOT"
+val releaseVersion = "1.6.5"
+val developmentVersion = "1.6.6-SNAPSHOT"
 
 version = if( java.lang.Boolean.getBoolean( "release" ) ) releaseVersion else developmentVersion
 

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

@@ -49,6 +49,7 @@ import javax.swing.ImageIcon;
 import javax.swing.JComponent;
 import javax.swing.JDialog;
 import javax.swing.JFrame;
+import javax.swing.JMenuBar;
 import javax.swing.LookAndFeel;
 import javax.swing.PopupFactory;
 import javax.swing.RootPaneContainer;
@@ -264,6 +265,12 @@ public abstract class FlatLaf
 				}
 			};
 			Toolkit toolkit = Toolkit.getDefaultToolkit();
+
+			// make sure that AWT desktop properties are initialized (on Linux)
+			// before invoking toolkit.addPropertyChangeListener()
+			// https://github.com/JFormDesigner/FlatLaf/issues/405#issuecomment-960242342
+			toolkit.getDesktopProperty( "dummy" );
+
 			toolkit.addPropertyChangeListener( desktopPropertyName, desktopPropertyListener );
 			if( desktopPropertyName2 != null )
 				toolkit.addPropertyChangeListener( desktopPropertyName2, desktopPropertyListener );
@@ -872,12 +879,23 @@ public abstract class FlatLaf
 
 	/**
 	 * Revalidate and repaint all displayable frames and dialogs.
+	 * <p>
+	 * Useful to update UI after changing {@code TitlePane.menuBarEmbedded}.
 	 *
 	 * @since 1.1.2
 	 */
 	public static void revalidateAndRepaintAllFramesAndDialogs() {
 		for( Window w : Window.getWindows() ) {
 			if( isDisplayableFrameOrDialog( w ) ) {
+				// revalidate menu bar
+				JMenuBar menuBar = (w instanceof JFrame)
+					? ((JFrame)w).getJMenuBar()
+					: (w instanceof JDialog
+						? ((JDialog)w).getJMenuBar()
+						: null);
+				if( menuBar != null )
+					menuBar.revalidate();
+
 				w.revalidate();
 				w.repaint();
 			}
@@ -886,6 +904,9 @@ public abstract class FlatLaf
 
 	/**
 	 * Repaint all displayable frames and dialogs.
+	 * <p>
+	 * Useful to update UI after changing {@code TitlePane.unifiedBackground},
+	 * {@code MenuItem.selectionType} or {@code Component.hideMnemonics}.
 	 *
 	 * @since 1.1.2
 	 */

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

@@ -17,6 +17,7 @@
 package com.formdev.flatlaf;
 
 import java.awt.Font;
+import java.awt.FontMetrics;
 import java.awt.GraphicsConfiguration;
 import java.awt.GraphicsEnvironment;
 import java.awt.Toolkit;
@@ -28,7 +29,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.StringTokenizer;
-
+import javax.swing.text.StyleContext;
 import com.formdev.flatlaf.util.LoggingFacade;
 import com.formdev.flatlaf.util.StringUtils;
 import com.formdev.flatlaf.util.SystemInfo;
@@ -121,14 +122,25 @@ class LinuxFontPolicy
 		for(;;) {
 			Font font = createFont( family, style, size, dsize );
 
-			// if the font family does not match any font on the system, "Dialog" family is returned
-			if( !"Dialog".equals( font.getFamily() ) || "Dialog".equals( family ) )
+			if( Font.DIALOG.equals( family ) )
 				return font;
 
+			// if the font family does not match any font on the system, "Dialog" family is returned
+			if( !Font.DIALOG.equals( font.getFamily() ) ) {
+				// check for font problems
+				// - font height much larger than expected (e.g. font Inter; Oracle Java 8)
+				// - character width is zero (e.g. font Cantarell; Fedora; Oracle Java 8)
+				FontMetrics fm = StyleContext.getDefaultStyleContext().getFontMetrics( font );
+				if( fm.getHeight() > size * 2 || fm.stringWidth( "a" ) == 0 )
+					return createFont( Font.DIALOG, style, size, dsize );
+
+				return font;
+			}
+
 			// find last word in family
 			int index = family.lastIndexOf( ' ' );
 			if( index < 0 )
-				return createFont( "Dialog", style, size, dsize );
+				return createFont( Font.DIALOG, style, size, dsize );
 
 			// check whether last work contains some font weight (e.g. Ultra-Bold or Heavy)
 			String lastWord = family.substring( index + 1 ).toLowerCase();

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

@@ -108,7 +108,7 @@ public class FlatCaret
 	protected void selectAllOnFocusGained() {
 		JTextComponent c = getComponent();
 		Document doc = c.getDocument();
-		if( doc == null || !c.isEnabled() || !c.isEditable() )
+		if( doc == null || !c.isEnabled() || !c.isEditable() || FlatUIUtils.isCellEditor( c ) )
 			return;
 
 		Object selectAllOnFocusPolicy = c.getClientProperty( SELECT_ALL_ON_FOCUS_POLICY );

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

@@ -260,7 +260,10 @@ public class FlatComboBoxUI
 			public void layoutContainer( Container parent ) {
 				super.layoutContainer( parent );
 
-				if( arrowButton != null ) {
+				// on macOS, a Swing combo box is used for AWT component java.awt.Choice
+				// and the font may be (temporary) null
+
+				if( arrowButton != null && comboBox.getFont() != null ) {
 					// limit button width to height of a raw combobox (without insets)
 					FontMetrics fm = comboBox.getFontMetrics( comboBox.getFont() );
 					int maxButtonWidth = fm.getHeight() + scale( padding.top ) + scale( padding.bottom );
@@ -495,11 +498,20 @@ public class FlatComboBoxUI
 		c.setBackground( getBackground( enabled ) );
 		c.setForeground( getForeground( enabled ) );
 
+		// make renderer component temporary non-opaque to avoid that renderer paints
+		// background outside of border if combobox uses larger arc for edges
+		// (e.g. FlatClientProperties.COMPONENT_ROUND_RECT is true)
+		if( c instanceof JComponent )
+			((JComponent)c).setOpaque( false );
+
 		boolean shouldValidate = (c instanceof JPanel);
 
 		paddingBorder.install( c );
 		currentValuePane.paintComponent( g, c, comboBox, bounds.x, bounds.y, bounds.width, bounds.height, shouldValidate );
 		paddingBorder.uninstall();
+
+		if( c instanceof JComponent )
+			((JComponent)c).setOpaque( true );
 	}
 
 	@Override
@@ -796,7 +808,9 @@ public class FlatComboBoxUI
 			this.padding = padding;
 		}
 
-		void install( Component c ) {
+		// using synchronized to avoid problems with code that modifies combo box
+		// (model, selection, etc) not on AWT thread (which should be not done)
+		synchronized void install( Component c ) {
 			if( !(c instanceof JComponent) )
 				return;
 
@@ -819,7 +833,7 @@ public class FlatComboBoxUI
 
 			// remember old border and replace it
 			rendererBorder = jc.getBorder();
-			rendererComponent.setBorder( this );
+			jc.setBorder( this );
 		}
 
 		/**
@@ -828,7 +842,7 @@ public class FlatComboBoxUI
 		 * there is no single place to uninstall it.
 		 * This is the reason why this method is called from various places.
 		 */
-		void uninstall() {
+		synchronized void uninstall() {
 			if( rendererComponent == null )
 				return;
 
@@ -839,9 +853,9 @@ public class FlatComboBoxUI
 		}
 
 		@Override
-		public Insets getBorderInsets( Component c, Insets insets ) {
+		synchronized public Insets getBorderInsets( Component c, Insets insets ) {
 			Insets padding = scale( this.padding );
-			if( rendererBorder != null ) {
+			if( rendererBorder != null && !(rendererBorder instanceof CellPaddingBorder) ) {
 				Insets insideInsets = rendererBorder.getBorderInsets( c );
 				insets.top = Math.max( padding.top, insideInsets.top );
 				insets.left = Math.max( padding.left, insideInsets.left );

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

@@ -262,12 +262,20 @@ public class FlatFileChooserUI
 
 	@Override
 	public FileView getFileView( JFileChooser fc ) {
-		return fileView;
+		return doNotUseSystemIcons() ? super.getFileView( fc ) : fileView;
 	}
 
 	@Override
 	public void clearIconCache() {
-		fileView.clearIconCache();
+		if( doNotUseSystemIcons() )
+			super.clearIconCache();
+		else
+			fileView.clearIconCache();
+	}
+
+	private boolean doNotUseSystemIcons() {
+		// Java 17 32bit craches on Windows when using system icons
+		return SystemInfo.isWindows && SystemInfo.isJava_17_orLater && !SystemInfo.isX86_64;
 	}
 
 	//---- class FlatFileView -------------------------------------------------

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

@@ -121,6 +121,10 @@ public class FlatPopupFactory
 				popupWindow.getGraphicsConfiguration() == owner.getGraphicsConfiguration() )
 			  return popup;
 
+			// avoid endless loop (should newer happen; PopupFactory cache size is 5)
+			if( ++count > 10 )
+				return popup;
+
 			// remove contents component from popup window
 			if( popupWindow instanceof JWindow )
 				((JWindow)popupWindow).getContentPane().removeAll();
@@ -128,10 +132,6 @@ public class FlatPopupFactory
 			// dispose unused popup
 			// (do not invoke popup.hide() because this would cache the popup window)
 			popupWindow.dispose();
-
-			// avoid endless loop (should newer happen; PopupFactory cache size is 5)
-			if( ++count > 10 )
-				return popup;
 		}
 	}
 

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

@@ -508,7 +508,7 @@ public class FlatTitlePane
 
 	protected void menuBarLayouted() {
 		updateNativeTitleBarHeightAndHitTestSpotsLater();
-		revalidate();
+		doLayout();
 	}
 
 /*debug

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

@@ -263,9 +263,19 @@ public class FlatTreeUI
 		boolean isDropRow = isDropRow( row );
 		boolean needsSelectionPainting = (isSelected || isDropRow) && isPaintSelection();
 
-		// do not paint row if editing, except if selection needs painted
-		if( isEditing && !needsSelectionPainting )
+		// do not paint row if editing
+		if( isEditing ) {
+			// paint wide selection
+			// (do not access cell renderer here to avoid side effect
+			// if renderer component is also used as editor component)
+			if( isSelected && isWideSelection() ) {
+				Color oldColor = g.getColor();
+				g.setColor( selectionInactiveBackground );
+				paintWideSelection( g, clipBounds, insets, bounds, path, row, isExpanded, hasBeenExpanded, isLeaf );
+				g.setColor( oldColor );
+			}
 			return;
+		}
 
 		boolean hasFocus = FlatUIUtils.isPermanentFocusOwner( tree );
 		boolean cellHasFocus = hasFocus && (row == getLeadSelectionRow());
@@ -322,14 +332,7 @@ public class FlatTreeUI
 
 			if( isWideSelection() ) {
 				// wide selection
-				g.fillRect( 0, bounds.y, tree.getWidth(), bounds.height );
-
-				// paint expand/collapse icon
-				// (was already painted before, but painted over with wide selection)
-				if( shouldPaintExpandControl( path, row, isExpanded, hasBeenExpanded, isLeaf ) ) {
-					paintExpandControl( g, clipBounds, insets, bounds,
-						path, row, isExpanded, hasBeenExpanded, isLeaf );
-				}
+				paintWideSelection( g, clipBounds, insets, bounds, path, row, isExpanded, hasBeenExpanded, isLeaf );
 			} else {
 				// non-wide selection
 				paintCellBackground( g, rendererComponent, bounds );
@@ -353,8 +356,7 @@ public class FlatTreeUI
 		}
 
 		// paint renderer
-		if( !isEditing )
-			rendererPane.paintComponent( g, rendererComponent, tree, bounds.x, bounds.y, bounds.width, bounds.height, true );
+		rendererPane.paintComponent( g, rendererComponent, tree, bounds.x, bounds.y, bounds.width, bounds.height, true );
 
 		// restore background selection color and border selection color
 		if( oldBackgroundSelectionColor != null )
@@ -363,6 +365,19 @@ public class FlatTreeUI
 			((DefaultTreeCellRenderer)rendererComponent).setBorderSelectionColor( oldBorderSelectionColor );
 	}
 
+	private void paintWideSelection( Graphics g, Rectangle clipBounds, Insets insets, Rectangle bounds,
+		TreePath path, int row, boolean isExpanded, boolean hasBeenExpanded, boolean isLeaf )
+	{
+		g.fillRect( 0, bounds.y, tree.getWidth(), bounds.height );
+
+		// paint expand/collapse icon
+		// (was already painted before, but painted over with wide selection)
+		if( shouldPaintExpandControl( path, row, isExpanded, hasBeenExpanded, isLeaf ) ) {
+			paintExpandControl( g, clipBounds, insets, bounds,
+				path, row, isExpanded, hasBeenExpanded, isLeaf );
+		}
+	}
+
 	private void paintCellBackground( Graphics g, Component rendererComponent, Rectangle bounds ) {
 		int xOffset = 0;
 		int imageOffset = 0;

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

@@ -163,11 +163,18 @@ class FlatWindowsNativeWindowBorder
 			return;
 
 		// install
-		WndProc wndProc = new WndProc( window );
-		if( wndProc.hwnd == 0 )
-			return;
+		try {
+			WndProc wndProc = new WndProc( window );
+			if( wndProc.hwnd == 0 )
+				return;
 
-		windowsMap.put( window, wndProc );
+			windowsMap.put( window, wndProc );
+		} catch( UnsatisfiedLinkError ex ) {
+			// catch for the case that the operating system prevents execution of DLL
+			// (e.g. if DLLs in temp folder are restricted)
+			// --> continue application without custom decorations
+			LoggingFacade.INSTANCE.logSevere( null, ex );
+		}
 	}
 
 	private void uninstall( Window window ) {

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

@@ -46,6 +46,7 @@ public class SystemInfo
 	public static final boolean isJava_9_orLater;
 	public static final boolean isJava_11_orLater;
 	public static final boolean isJava_15_orLater;
+	/** @since 2 */ public static final boolean isJava_17_orLater;
 
 	// Java VMs
 	public static final boolean isJetBrainsJVM;
@@ -82,6 +83,7 @@ public class SystemInfo
 		isJava_9_orLater = (javaVersion >= toVersion( 9, 0, 0, 0 ));
 		isJava_11_orLater = (javaVersion >= toVersion( 11, 0, 0, 0 ));
 		isJava_15_orLater = (javaVersion >= toVersion( 15, 0, 0, 0 ));
+		isJava_17_orLater = (javaVersion >= toVersion( 17, 0, 0, 0 ));
 
 		// Java VMs
 		isJetBrainsJVM = System.getProperty( "java.vm.vendor", "Unknown" )

flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatLaf.properties

@@ -374,7 +374,7 @@ MenuItem.iconTextGap = 6
 MenuItem.textAcceleratorGap = 24
 MenuItem.textNoAcceleratorGap = 6
 MenuItem.acceleratorArrowGap = 2
-MenuItem.acceleratorDelimiter = -
+MenuItem.acceleratorDelimiter = +
 [mac]MenuItem.acceleratorDelimiter = 
 
 # for MenuItem.selectionType = underline

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatAWTTest.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2021 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.testing;
+
+import java.awt.*;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import com.formdev.flatlaf.FlatLightLaf;
+
+/**
+ * Used to test AWT components on macOS, which internally use Swing.
+ *
+ * @author Karl Tauber
+ */
+public class FlatAWTTest
+{
+	public static void main( String[] args ) {
+		EventQueue.invokeLater( () -> {
+			FlatLightLaf.setup();
+
+			Frame frame = new Frame( "FlatAWTTest" );
+			frame.addWindowListener( new WindowAdapter() {
+				@Override
+				public void windowClosing( WindowEvent e ) {
+					System.exit( 0 );
+				}
+			} );
+			frame.setLayout( new FlowLayout() );
+
+			frame.add( new Label( "text" ) );
+			frame.add( new Button( "text" ) );
+			frame.add( new Checkbox( "text" ) );
+
+			CheckboxGroup checkboxGroup = new CheckboxGroup();
+			frame.add( new Checkbox( "radio 1", true, checkboxGroup ) );
+			frame.add( new Checkbox( "radio 2", false, checkboxGroup ) );
+			frame.add( new Checkbox( "radio 3", false, checkboxGroup ) );
+
+			Choice choice = new Choice();
+			choice.add( "item 1" );
+			choice.add( "item 2" );
+			choice.add( "item 3" );
+			frame.add( choice );
+
+			frame.add( new TextField( "text" ) );
+			frame.add( new TextArea( "text" ) );
+
+			List list = new List();
+			list.add( "item 1" );
+			list.add( "item 2" );
+			frame.add( list );
+
+			frame.add( new Scrollbar() );
+			frame.add( new ScrollPane() );
+			frame.add( new Panel() );
+			frame.add( new Canvas() );
+
+			frame.setSize( 800, 600 );
+			frame.setVisible( true );
+		});
+	}
+}

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatComponentsTest.java

@@ -1621,6 +1621,7 @@ public class FlatComponentsTest
 //		customRenderer.setBorder( new LineBorder( Color.red ) );
 //		comboBox1.setRenderer( customRenderer );
 //		comboBox3.setRenderer( customRenderer );
+//		comboBox5.setRenderer( new DefaultListCellRenderer() );
 
 		// for testing issue #382
 //		spinner1.setModel( new SpinnerNumberModel( 0, null, 100, 1 ) );

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatCustomBordersTest.java

@@ -34,7 +34,7 @@ public class FlatCustomBordersTest
 	private static final Color RED = new Color( 0x60ff0000, true );
 	private static final Color GREEN = new Color( 0x6000ff00, true );
 	private static final Color MAGENTA = new Color( 0x60ff00ff, true );
-	private static final Color ORANGE = new Color( 0x60ffc800, true );
+	private static final Color BLUE = new Color( 0x300000ff, true );
 
 	public static void main( String[] args ) {
 		SwingUtilities.invokeLater( () -> {
@@ -127,7 +127,7 @@ public class FlatCustomBordersTest
 	@SuppressWarnings( "unchecked" )
 	private void applySpecialComboBoxRenderers() {
 		BasicComboBoxRenderer sharedRenderer = new BasicComboBoxRenderer();
-		sharedRenderer.setBorder( new LineBorder( ORANGE, UIScale.scale( 2 ) ) );
+		sharedRenderer.setBorder( new LineBorder( BLUE, UIScale.scale( 2 ) ) );
 		comboBox29.setRenderer( sharedRenderer );
 		comboBox30.setRenderer( sharedRenderer );
 
@@ -160,7 +160,7 @@ public class FlatCustomBordersTest
 	}
 
 	private void applyCustomComboBoxEditorBorder( JComboBox<String> comboBox ) {
-		applyCustomComboBoxEditorBorder( comboBox, new LineBorder( ORANGE, UIScale.scale( 6 ) ) );
+		applyCustomComboBoxEditorBorder( comboBox, new LineBorder( BLUE, UIScale.scale( 6 ) ) );
 	}
 
 	private void applyCustomComboBoxEditorBorderWithIcon( JComboBox<String> comboBox ) {
@@ -180,7 +180,7 @@ public class FlatCustomBordersTest
 	}
 
 	private void applyCustomComboBoxRendererBorder( JComboBox<String> comboBox ) {
-		applyCustomComboBoxRendererBorder( comboBox, new LineBorder( ORANGE, UIScale.scale( 6 ) ) );
+		applyCustomComboBoxRendererBorder( comboBox, new LineBorder( BLUE, UIScale.scale( 6 ) ) );
 	}
 
 	private void applyCustomComboBoxRendererBorderWithIcon( JComboBox<String> comboBox ) {

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatStressTest.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2021 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.testing;
+
+import java.awt.Container;
+import java.awt.FlowLayout;
+import java.util.Random;
+import javax.swing.JComboBox;
+import javax.swing.JComponent;
+import javax.swing.JFrame;
+import javax.swing.SwingUtilities;
+import com.formdev.flatlaf.FlatClientProperties;
+import com.formdev.flatlaf.FlatLightLaf;
+
+/**
+ * @author Karl Tauber
+ */
+public class FlatStressTest
+{
+	public static void main( String[] args ) {
+		SwingUtilities.invokeLater( () -> {
+			FlatLightLaf.setup();
+			new FlatStressTest();
+		} );
+	}
+
+	protected FlatStressTest() {
+		JFrame frame = new JFrame( "FlatStressTest" );
+		frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
+
+		Container contentPane = frame.getContentPane();
+		contentPane.setLayout( new FlowLayout() );
+
+		contentPane.add( createStressTest() );
+
+		frame.setSize( 800, 600 );
+		frame.setLocationRelativeTo( null );
+		frame.setVisible( true );
+	}
+
+	private JComponent createStressTest() {
+		return createComboBoxStressTest();
+	}
+
+	// for https://github.com/JFormDesigner/FlatLaf/issues/432
+	// simulates StackOverflowError in FlatComboBoxUI when doing stuff in various threads
+	//
+	// requires adding `Thread.sleep( 1 );` to `FlatComboBoxUI.CellPaddingBorder.install()`
+	// after invocation of `uninstall()`
+	private JComponent createComboBoxStressTest() {
+		Random random = new Random();
+
+		JComboBox<String> comboBox = new JComboBox<>();
+		comboBox.putClientProperty( FlatClientProperties.MINIMUM_WIDTH, 0 );
+		for( int i = 0; i < 100; i++ )
+			comboBox.addItem( Integer.toString( random.nextInt() ) );
+
+		Thread thread = new Thread( () -> {
+			for(;;) {
+				comboBox.setSelectedIndex( random.nextInt( comboBox.getItemCount() ) );
+				comboBox.putClientProperty( FlatClientProperties.MINIMUM_WIDTH, random.nextInt( 500 ) );
+			}
+		});
+		thread.setDaemon( true );
+		thread.start();
+
+		return comboBox;
+	}
+}