Demo: on macOS use apple.awt.fullWindowContent and apple.awt.transparentTitleBar

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

@@ -89,6 +89,24 @@ class DemoFrame
 
 			// do not use HTML text on macOS
 			htmlMenuItem.setText( "some text" );
+
+			// see https://www.formdev.com/flatlaf/macos/
+			if( SystemInfo.isMacFullWindowContentSupported ) {
+				getRootPane().putClientProperty( "apple.awt.fullWindowContent", true );
+				getRootPane().putClientProperty( "apple.awt.transparentTitleBar", true );
+
+				// hide window title
+				if( SystemInfo.isJava_17_orLater )
+					getRootPane().putClientProperty( "apple.awt.windowTitleVisible", false );
+				else
+					setTitle( null );
+
+				// add gap to left side of toolbar
+				toolBar.add( Box.createHorizontalStrut( 70 ), 0 );
+			}
+
+			// enable full screen mode for this window
+			getRootPane().putClientProperty( "apple.awt.fullscreenable", true );
 		}
 
 		// integrate into macOS screen menu

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

@@ -38,6 +38,8 @@ public class FlatLafDemo
 	public static void main( String[] args ) {
 		// macOS
 		if( SystemInfo.isMacOS ) {
+			// see https://www.formdev.com/flatlaf/macos/
+
 			// enable screen menu bar
 			// (moves menu bar from JFrame window to top of screen)
 			System.setProperty( "apple.laf.useScreenMenuBar", "true" );
@@ -51,6 +53,7 @@ public class FlatLafDemo
 			//   - "system": use current macOS appearance (light or dark)
 			//   - "NSAppearanceNameAqua": use light appearance
 			//   - "NSAppearanceNameDarkAqua": use dark appearance
+			// (needs to be set on main thread; setting it on AWT thread does not work)
 			System.setProperty( "apple.awt.application.appearance", "system" );
 		}