Win: Send Alt-F4 to server if KB grabbing enabled

Closes #434

ChangeLog.md

@@ -112,6 +112,9 @@ sized, if multi-screen spanning was enabled, the scaled remote desktop was
 larger than the viewer window, and "Displays have separate Spaces" was enabled
 in the system settings.
 
+23. The Windows TurboVNC Viewer now sends Alt-F4 keystrokes to the VNC server
+if keyboard grabbing is enabled.
+
 
 3.0.3
 =====

java/com/turbovnc/vncviewer/DesktopWindow.java

@@ -1,4 +1,4 @@
-/* Copyright (C) 2010, 2012-2013, 2015-2018, 2020-2024 D. R. Commander.
+/* Copyright (C) 2010, 2012-2013, 2015-2018, 2020-2025 D. R. Commander.
  *                                                     All Rights Reserved.
  * Copyright (C) 2011-2013 Brian P. Hinz
  * Copyright (C) 2009 Paul Donohue.  All Rights Reserved.
@@ -99,9 +99,13 @@ class DesktopWindow extends JPanel implements Runnable, MouseListener,
       private final KeyEventDispatcher keyEventDispatcher =
         new KeyEventDispatcher() {
         public boolean dispatchKeyEvent(KeyEvent e) {
-          if ((e.getKeyCode() == 18 &&
+          if ((e.getKeyCode() == KeyEvent.VK_ALT &&
                e.getKeyLocation() == KeyEvent.KEY_LOCATION_LEFT) ||
-              e.getKeyCode() == 121) {
+              e.getKeyCode() == KeyEvent.VK_F10 ||
+              // Also send Alt-F4 to the VNC server if the keyboard is grabbed.
+              (Utils.isWindows() && VncViewer.isKeyboardGrabbed(cc.viewport) &&
+               e.getKeyCode() == KeyEvent.VK_F4 &&
+               e.getModifiersEx() == KeyEvent.ALT_DOWN_MASK)) {
             if (e.getID() == KeyEvent.KEY_PRESSED)
               cc.desktop.keyPressed(e);
             else if (e.getID() == KeyEvent.KEY_RELEASED)