transparent jframe background?

Ok I'm a little self conscious though. Undecided

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public static final int WIDTH = 437;
public static final int HEIGHT = 127;
public static BufferedImage buffer = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_ARGB);

...

JFrame detached = new JFrame();
detached.setSize(WIDTH, HEIGHT);
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
detached.setLocation((dim.width - WIDTH) / 2, (dim.height - HEIGHT) / 2);
detached.setUndecorated(true);
detached.setBackground(new Color(0, 0, 0, 0));

JPanel panel = new JPanel() {

   private static final long serialVersionUID = 1L;

         @Override
         public void paintComponent(Graphics g_) { // call panel.repaint() as necessary
            Graphics2D g2 = (Graphics2D) buffer.getGraphics();
            g2.setComposite(AlphaComposite.getInstance(AlphaComposite.CLEAR));
            g2.fillRect(0, 0, WIDTH, HEIGHT);
            g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC));
            draw(g2); // draw the actual menu
            g2.dispose();

            Graphics2D g = (Graphics2D) g_;
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC)); // only draws source, effectively clearing old image
            g.drawImage(buffer, 0, 0, null);
            g.dispose();
         }

};
panel.addMouseListener(MenuMouseListener.instance);
panel.addMouseMotionListener(MenuMouseListener.instance);
panel.setIgnoreRepaint(true);

detached.add(panel);

detached.setVisible(true);

...

// This is how I handled dragging because the JFrame is now undecorated

   private static class MenuMouseListener implements MouseListener, MouseMotionListener {

      public static final MenuMouseListener instance = new MenuMouseListener();

      private MenuMouseListener() {
         
      }

      private int locX;
      private int locY;

      @Override
      public void mouseDragged(MouseEvent e) {
         if ((e.getModifiersEx() & MouseEvent.BUTTON1_DOWN_MASK) == MouseEvent.BUTTON1_DOWN_MASK) {
            detached.setLocation(e.getXOnScreen() - locX, e.getYOnScreen() - locY);
         }
      }

      @Override
      public void mouseMoved(MouseEvent e) {
         
      }

      @Override
      public void mouseClicked(MouseEvent e) {
         
      }

      @Override
      public void mousePressed(MouseEvent e) {
         if (e.getModifiers() == MouseEvent.BUTTON1_MASK) {
            locX = e.getX();
            locY = e.getY();
         }
      }

      @Override
      public void mouseReleased(MouseEvent e) {
         
      }

      @Override
      public void mouseEntered(MouseEvent e) {
         
      }

      @Override
      public void mouseExited(MouseEvent e) {
         
      }
      
   }

EDIT: Actually you can just clear the old graphics by only drawing the source using AlphaComposite.SRC