private void initUI() {

		toolkit = this.getToolkit();

		menu = new JPopupMenu();

		JMenuItem menuItemBeep = new JMenuItem("Beep");
		menuItemBeep.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				toolkit.beep();
			}
		});
		menu.add(menuItemBeep);

		JMenuItem menuItemClose = new JMenuItem("Close");
		menuItemClose.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				System.exit(0);
			}
		});
		menu.add(menuItemClose);

		this.addMouseListener(new MouseAdapter() {
			@Override
			public void mouseReleased(MouseEvent e) {
				if (e.getButton() == MouseEvent.BUTTON3) {
					menu.show(e.getComponent(), e.getX(), e.getY());
				}
			}
		});

		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setSize(250, 200);
		this.setLocationRelativeTo(null);
	}