JWindow的右键菜单在失去焦点后不能自动消失

import java.awt.Point;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import javax.swing.JMenuItem;

import javax.swing.JPopupMenu;

import javax.swing.JWindow;



public class Main {



	public Main() {

	}



	static public class PopupListener extends MouseAdapter {

		JPopupMenu menu;



		public PopupListener(JPopupMenu menu) {

			this.menu = menu;

		}



		public void mousePressed(MouseEvent e) {

			showPopup(e);

		}



		public void mouseReleased(MouseEvent e) {

			showPopup(e);

		}



		private void showPopup(MouseEvent e) {

			if (e.isPopupTrigger()) {

				 

				menu.show(e.getComponent(), e.getX(), e.getY());



				System.out.println("Showing menu at "

						+ menu.getLocationOnScreen() + " isVisible: "

						+ menu.isVisible() + " isValid: " + menu.isValid());

			}

		}

	}



	 

	public static void main(String[] args) {

		JWindow window = new JWindow();

		window.setBounds(10, 10, 100, 100);



		JPopupMenu popupMenu = new JPopupMenu();

		JMenuItem quit = new JMenuItem("Quit");

		quit.addActionListener(new ActionListener() {

			public void actionPerformed(ActionEvent e) {

				System.exit(0);

			}

		});

		popupMenu.add(quit);



		window.addMouseListener(new PopupListener(popupMenu));

		



		window.setFocusable(true);



		window.validate();

		window.setVisible(true);

	}



}