Q:

JPopupMenu doesn't dissapear/move when minimising/moving the JFrame it is in

I am making an mp3 player, with several JLists in my JFrame. When I right click on a JList item, a popup with some options for that song appears. But when this popup is visible, and I minimise my JFrame, this popup stays visible! Also, when the popup is visible, and I drag my JFrame to somewhere else on the screen, the popup stays on it's original position (so it does not stay on the same position relative to the JFrame)... Can someone please help me out with this? I tried to strip down this class as much as possible :)
I would be really grateful if someone could help me out !!
Joe
public class playListPanel extends JPanel implements MouseListener {
    private DefaultListModel model;
    private Interface interFace;
    private JList list;
    private boolean emptyPlaylist;
    private ArrayList<Song> currentPlayList;
    private Song rightClickedSong;
    private JPopupMenu popup;
    private Point panelLocation;

    public playListPanel(Interface interFace) // Interface extends JFrame,
                                                // playListPanel is a part of
                                                // this JFrame.
    {
        this.interFace = interFace;
        this.panelLocation = new Point(559, 146);
        setBackground(SystemColor.controlHighlight);
        setBorder(new TitledBorder(null, "", TitledBorder.LEADING,
                TitledBorder.TOP, null, null));
        setBounds((int) panelLocation.getX(), (int) panelLocation.getY(), 698,
                368);
        setLayout(null);

        currentPlayList = new ArrayList<Song>();

        model = new DefaultListModel();
        list = new JList(model);
        list.setVisible(true);
        list.addMouseListener(this);

        JScrollPane scrollPane = new JScrollPane(list);
        scrollPane.setBounds(5, 5, 688, 357);
        add(scrollPane);

        emptyPlaylist = true;
    }

    private void openMenuPopup(Point point)
    {
        removePopup();
        popup = new JPopupMenu();
        int x = (int) point.getX();
        int y = (int) point.getY();
        popup.setLocation((int) (x+panelLocation.getX()),(int) (y+panelLocation.getY()));
        //popup.setLabel("popup voor playlist");
        JMenuItem removeSong;
        popup.add(removeSong = new JMenuItem("Remove Song from Playlist", new ImageIcon("image.jpg")));

        ActionListener menuListener = new ActionListener()
        {
              public void actionPerformed(ActionEvent event) 
              {
                if(event.getActionCommand().equals("Remove Song from Playlist"))
                {
                    System.out.println("Remove Song from Playlist");
                    interFace.getPlaylistManager().removeOneSong(rightClickedSong);
                    removePopup();
                }

        };

        //ADD THE LISTENERS TO THE MENU ITEMS
        removeSong.addActionListener(menuListener);
        popup.setVisible(true);
    }

    public void removePopup()
    {
        if(popup!==null)
        {
            popup.setVisible(false);
            System.out.println("popup removed");
        }
    }

    private int getRow(Point point) {
        return list.locationToIndex(point);
    }

    public void refreshPlayList(ArrayList<Song> playlist) {
        this.currentPlayList = playlist;

        model.clear();
        for (Song song : playlist) {
            model.add(model.getSize(), song.getPlaylistString());
        }
        list.setVisible(true);
    }

    public void highlightSong(int index) {
        list.setSelectedIndex(index);
    }

    public int getRowOfList(Point point) {
        return list.locationToIndex(point);
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        interFace.getPlaylistManager().doubleClickOnPlaylist(e);
    }

    @Override
    public void mouseEntered(MouseEvent arg0) {
    }

    @Override
    public void mouseExited(MouseEvent arg0) {
    }

    @Override
    public void mousePressed(MouseEvent e) {
        if (SwingUtilities.isRightMouseButton(e)) {
            rightClickedSong = currentPlayList.get(getRow(e.getPoint()));
            openMenuPopup(e.getPoint());
            System.out.println("should open popup at "
                    + e.getPoint().toString());
        }

    }

    @Override
    public void mouseReleased(MouseEvent arg0) {
    }
}

A:

There are some basic flaws in the way you are handling click for showing popup.
It is not advisable to call popup.setVisible in simple scenarios like this. Instead, you may rely on its default behavior. Also, better to use e.isPopupTrigger() than to  check SwingUtilities.isRightMouseButton(e) to show popup.
You may do something like the following :
//at classlevel,
private JPopupMenu popup = new JPopupMenu();
//create a Popuplistener
PopupListener pl = new PopupListener();
list.addMouseListener(pl);

//Implementation of your popuplistener
  class PopupListener extends MouseAdapter {
    public void mousePressed(MouseEvent e) {
      maybeShowPopup(e);
    }

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

    private void maybeShowPopup(MouseEvent e) {
      if (e.isPopupTrigger())
        //e.getSource - and construct your popup as required.
        //and then.
        popup.show(((JApplet) e.getComponent()).getContentPane(), e
            .getX(), e.getY());
    }
  }

