如何检测＆＃34; ALT + TAB＆＃34; SWT Shell中的关键事件？

Question

我想在SWT Shell中检测关键事件 Alt + Tab 键。按Tab键时，必须按 Alt 键。 我已尝试使用以下内容，但未检测到 Alt + Tab 。

public static void main(String[] args) 
  {
    Display display = new Display ();
    final Shell shell = new Shell (display);
    final Color green = display.getSystemColor (SWT.COLOR_GREEN);
    final Color orig = shell.getBackground();

    display.addFilter(SWT.KeyDown, new Listener() {

        public void handleEvent(Event e) {
            if(((e.stateMask & SWT.ALT) == SWT.ALT) && (e.keyCode == SWT.TAB))
            {
                System.out.println("From Display I am the Key down !!" );
            }
        }
    });
    shell.addKeyListener(new KeyListener() {
      public void keyReleased(KeyEvent e) {
          if(((e.stateMask & SWT.ALT) == SWT.ALT) && (e.keyCode == SWT.TAB))
          {
              shell.setBackground(orig);
              System.out.println("Key up ALT +TAB Detact !!");
          }
      }
      public void keyPressed(KeyEvent e) {
          if(((e.stateMask & SWT.ALT) == SWT.ALT) && (e.keyCode ==  SWT.TAB))
          {
              shell.setBackground(green);
              System.out.println("Key down  ALT +TAB Detact!!");
          }
      }
   });
    shell.setSize (200, 200);
    shell.open ();
    while (!shell.isDisposed()) {
    if (!display.readAndDispatch ()) display.sleep ();
    }
    display.dispose ();
}