If you open a jpopupmenu and you move the window to which it is attached, the jpopupmenu should get invisble. it doesent and stays where it is.
here a testcase, just open the menu and move the menu (while the menu is open)
this is the same testcase that also show the bug that the jmenuitem or the jpopupmenu (i think the later?) isnt updated correctly if the name of a item changes.  it also shows the bug of non resizable jframes.

package test;

import java.awt.Dimension;

import javax.swing.*;        

public class SwingTest {
    private static void createAndShowGUI() {
    	
        JFrame frame = new JFrame("HelloWorldSwing");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        JMenuBar bar = new JMenuBar();
        JMenu menu = new JMenu("asdfasd");
        JMenuItem item1 = new JMenuItem("aa");
        menu.add(item1);
        bar.add(menu);
        
        frame.setSize(new Dimension(600, 450)); 
        frame.setResizable(true);
        frame.setJMenuBar(bar);
        item1.setText("Long name");
        frame.setVisible(true); 
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}