From 0880a3380c841409e244ff8afe867f510410eb04 Mon Sep 17 00:00:00 2001
From: Karl Tauber <karl@jformdesigner.com>
Date: Sun, 7 Jun 2020 23:22:57 +0200
Subject: [PATCH] Window decorations: hide drag border components if frame is
 maximized

---
 .../formdev/flatlaf/ui/FlatWindowResizer.java | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowResizer.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowResizer.java
index 3a5c8e65..969f27e5 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowResizer.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowResizer.java
@@ -32,6 +32,8 @@ import java.awt.event.ComponentListener;
 import java.awt.event.MouseEvent;
 import java.awt.event.MouseListener;
 import java.awt.event.MouseMotionListener;
+import java.awt.event.WindowEvent;
+import java.awt.event.WindowStateListener;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import javax.swing.JComponent;
@@ -47,7 +49,7 @@ import com.formdev.flatlaf.util.UIScale;
  */
 class FlatWindowResizer
 	extends JComponent
-	implements PropertyChangeListener, ComponentListener
+	implements PropertyChangeListener, WindowStateListener, ComponentListener
 {
 	private final static Integer WINDOW_RESIZER_LAYER = JLayeredPane.DRAG_LAYER + 1;
 
@@ -86,8 +88,10 @@ class FlatWindowResizer
 
 		Container parent = rootPane.getParent();
 		window = (parent instanceof Window) ? (Window) parent : null;
-		if( window instanceof Frame )
+		if( window instanceof Frame ) {
 			window.addPropertyChangeListener( "resizable", this );
+			window.addWindowStateListener( this );
+		}
 
 		updateVisibility();
 	}
@@ -96,8 +100,10 @@ class FlatWindowResizer
 	public void removeNotify() {
 		super.removeNotify();
 
-		if( window instanceof Frame )
+		if( window instanceof Frame ) {
 			window.removePropertyChangeListener( "resizable", this );
+			window.removeWindowStateListener( this );
+		}
 		window = null;
 
 		updateVisibility();
@@ -123,7 +129,7 @@ class FlatWindowResizer
 
 	private boolean isWindowResizable() {
 		if( window instanceof Frame )
-			return ((Frame)window).isResizable();
+			return ((Frame)window).isResizable() && (((Frame)window).getExtendedState() & Frame.MAXIMIZED_BOTH) == 0;
 		if( window instanceof Dialog )
 			return ((Dialog)window).isResizable();
 		return false;
@@ -134,6 +140,11 @@ class FlatWindowResizer
 		updateVisibility();
 	}
 
+	@Override
+	public void windowStateChanged( WindowEvent e ) {
+		updateVisibility();
+	}
+
 	@Override
 	public void componentResized( ComponentEvent e ) {
 		setBounds( 0, 0, rootPane.getWidth(), rootPane.getHeight() );