JPopupMenu 在applet中的应用

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JPopupMenu 在applet中的应用5

jpopupmenu在桌面应用程序中弹出后可以点击添加到它上面的组件，并触发组件对应的事件，并且jpopupmenu不隐藏，
可是将此组件放入到applet中弹出后，点击它上面添加的组件，就不会触发事件，并且jpopupmenu隐藏，这是什么原因，又没有什么解决办法。
代码如下：

import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JButton;
import javax.swing.JCheckBoxMenuItem;
import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JSeparator;
import javax.swing.JSlider;
import javax.swing.MenuElement;
import javax.swing.MenuSelectionManager;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.TitledBorder;
import javax.swing.event.PopupMenuEvent;
import javax.swing.event.PopupMenuListener;

public class MenuElementExample extends JPanel {

  public JPopupMenu popup;

  SliderMenuItem slider;

  int theValue = 0;

  public MenuElementExample() {

    popup = new JPopupMenu();
    slider = new SliderMenuItem();

    popup.add(slider);
    popup.add(new JSeparator());
    
    JButton jb = new JButton("Test");
    jb.addActionListener(new ActionListener(){

		public void actionPerformed(ActionEvent e) {
			
			System.out.println("Test is prass");
		}
    });
    popup.add(jb);
    popup.add(new JSeparator());
    
    JMenuItem ticks = new JCheckBoxMenuItem("Slider Tick Marks");
    ticks.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
        slider.setPaintTicks(!slider.getPaintTicks());
      }
    });
    JMenuItem labels = new JCheckBoxMenuItem("Slider Labels");
    labels.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
        slider.setPaintLabels(!slider.getPaintLabels());
      }
    });
    popup.add(ticks);
    popup.add(labels);
    popup.addPopupMenuListener(new PopupPrintListener());
    
    
    addMouseListener(new MousePopupListener());
  }

  // Inner class to check whether mouse events are the popup trigger
  class MousePopupListener extends MouseAdapter {
    public void mousePressed(MouseEvent e) {
      checkPopup(e);
    }

    public void mouseClicked(MouseEvent e) {
      checkPopup(e);
    }

    public void mouseReleased(MouseEvent e) {
      checkPopup(e);
    }

    private void checkPopup(MouseEvent e) {
      if (e.isPopupTrigger()) {
        popup.show(MenuElementExample.this, e.getX(), e.getY());
      }
    }
  }

  // Inner class to print information in response to popup events
  class PopupPrintListener implements PopupMenuListener {
    public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
    }

    public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
      theValue = slider.getValue();
      System.out.println("The value is now " + theValue);
    }

    public void popupMenuCanceled(PopupMenuEvent e) {
      System.out.println("Popup menu is hidden!");
      MenuElementExample.this.setVisible(true);
    }
  }

  public static void main(String s[]) {
    JFrame frame = new JFrame("Menu Element Example");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setContentPane(new MenuElementExample());
    frame.setSize(300, 300);
    frame.setVisible(true);
  }

  // Inner class that defines our special slider menu item
  class SliderMenuItem extends JSlider implements MenuElement {

    public SliderMenuItem() {
      setBorder(new CompoundBorder(new TitledBorder("Control"),
          new EmptyBorder(10, 10, 10, 10)));

      setMajorTickSpacing(20);
      setMinorTickSpacing(10);
    }

    public void processMouseEvent(MouseEvent e, MenuElement path[],
        MenuSelectionManager manager) {
    }

    public void processKeyEvent(KeyEvent e, MenuElement path[],
        MenuSelectionManager manager) {
    }

    public void menuSelectionChanged(boolean isIncluded) {
    }

    public MenuElement[] getSubElements() {
      return new MenuElement[0];
    }

    public Component getComponent() {
      return this;
    }
  }
}

applet运行代码：

import java.awt.AWTEvent;
import java.awt.BorderLayout;

import javax.swing.JApplet;

import jpopupmeun.MenuElementExample;

public class AppletTest extends JApplet {

	/* (non-Javadoc)
	 * @see java.applet.Applet#init()
	 */
	@Override
	public void init() {
		
		super.init();
		this.setLayout(new BorderLayout());
		
		this.enableEvents(AWTEvent.MOUSE_EVENT_MASK);
		
		MenuElementExample ex = new MenuElementExample();
		add(ex,BorderLayout.CENTER);
		
	}
	
}

Htmel文件：
<OBJECT classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
width="200" height="200"
codebase="">
<param name="code" value="AppletTest">
<param name="cache_option" value="NO">
</OBJECT>

Swing