Window decorations: make embedded menu bar make smaller if horizontal space is rare to avoid that embedded menu bar overlaps buttons

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

@@ -123,6 +123,14 @@ public class FlatMenuUI
 		};
 	}
 
+	@Override
+	public Dimension getMinimumSize( JComponent c ) {
+		// avoid that top-level menus (in menu bar) are made smaller if horizontal space is rare
+		// same code is in BasicMenuUI since Java 10
+		// see https://bugs.openjdk.java.net/browse/JDK-8178430
+		return ((JMenu)menuItem).isTopLevelMenu() ? c.getPreferredSize() : null;
+	}
+
 	@Override
 	protected Dimension getPreferredMenuItemSize( JComponent c, Icon checkIcon, Icon arrowIcon, int defaultTextIconGap ) {
 		return renderer.getPreferredMenuItemSize();

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

@@ -19,6 +19,7 @@ package com.formdev.flatlaf.ui;
 import java.awt.BorderLayout;
 import java.awt.Color;
 import java.awt.Component;
+import java.awt.Container;
 import java.awt.Dialog;
 import java.awt.Dimension;
 import java.awt.EventQueue;
@@ -165,7 +166,25 @@ public class FlatTitlePane
 
 		createButtons();
 
-		setLayout( new BorderLayout() );
+		setLayout( new BorderLayout() {
+			@Override
+			public void layoutContainer( Container target ) {
+				super.layoutContainer( target );
+
+				// make left panel (with embedded menu bar) smaller if horizontal space is rare
+				// to avoid that embedded menu bar overlaps button bar
+				Insets insets = target.getInsets();
+				int width = target.getWidth() - insets.left - insets.right;
+				if( leftPanel.getWidth() + buttonPanel.getWidth() > width ) {
+					int oldWidth = leftPanel.getWidth();
+					int newWidth = Math.max( width - buttonPanel.getWidth(), 0 );
+					leftPanel.setSize( newWidth, leftPanel.getHeight() );
+					if( !getComponentOrientation().isLeftToRight() )
+						leftPanel.setLocation( leftPanel.getX() + (oldWidth - newWidth), leftPanel.getY() );
+				}
+			}
+		} );
+
 		add( leftPanel, BorderLayout.LINE_START );
 		add( titleLabel, BorderLayout.CENTER );
 		add( buttonPanel, BorderLayout.LINE_END );

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

@@ -62,6 +62,7 @@ public class FlatTestFrame
 	private FlatInspector inspector;
 
 	public boolean useApplyComponentOrientation;
+	public boolean applyComponentOrientationToFrame;
 
 	public static FlatTestFrame create( String[] args, String title ) {
 		DemoPrefs.init( PREFS_ROOT_PATH );
@@ -439,7 +440,9 @@ public class FlatTestFrame
 			? ComponentOrientation.RIGHT_TO_LEFT
 			: ComponentOrientation.LEFT_TO_RIGHT;
 
-		if( useApplyComponentOrientation )
+		if( applyComponentOrientationToFrame )
+			applyComponentOrientation( orientation );
+		else if( useApplyComponentOrientation )
 			content.applyComponentOrientation( orientation );
 		else {
 			updateComponentsRecur( content, (c, type) -> {

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

@@ -40,6 +40,7 @@ public class FlatWindowDecorationsTest
 			JDialog.setDefaultLookAndFeelDecorated( true );
 
 			FlatTestFrame frame = FlatTestFrame.create( args, "FlatWindowDecorationsTest" );
+			frame.applyComponentOrientationToFrame = true;
 
 			// WARNING: Do not this in real-world programs.
 //			frame.setUndecorated( true );