Dragging a JPopupMenu around with a mouse. What am I doing wrong?

Question

Hello,
I need to move a JPopupMenu around with a mouse, but it isn' working out as expected.
Menu is being moved erraticaly, jumping here and there a bit, and lagging behind the mouse movements.
Although it is moving in general direction of mouse drags.
Anyone has an idea what am I doing wrong?
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class JPopupMenuDragTest {
    public static void main(String[] args) {
        new JPopupMenuDragTest();
    JPanel contents = new JPanel();
    DraggablePopupMenu popup = new DraggablePopupMenu();
    public JPopupMenuDragTest() {
        contents.setPreferredSize(new Dimension(512, 384));
        contents.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                popup.show(contents, e.getX(), e.getY());
        showFrame(contents);
    void showFrame(JPanel contents) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setContentPane(contents);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    class DraggablePopupMenu extends JPopupMenu implements MouseListener, MouseMotionListener {
        JButton btnDragger = new JButton("drag me");
        int clickx, clicky, menux, menuy;
        public DraggablePopupMenu() {
            add(btnDragger);
            btnDragger.addMouseListener(this);
            btnDragger.addMouseMotionListener(this);
        public void mousePressed(MouseEvent e) {
            clickx = e.getX();
            clicky = e.getY();
            Point locationOnScreen = getLocationOnScreen();
            menux = locationOnScreen.x;
            menuy = locationOnScreen.y;
        public void mouseDragged(MouseEvent e) {
            int xOffset = e.getX() - clickx;
            int yOffset = e.getY() - clicky;
            setLocation(menux + xOffset, menuy + yOffset);
        public void mouseClicked(MouseEvent e) {}
        public void mouseReleased(MouseEvent e) {}
        public void mouseEntered(MouseEvent e) {}
        public void mouseExited(MouseEvent e) {}
        public void mouseMoved(MouseEvent e) {}
}

Answer 1

Thanks, that kind of works. The point is, I have to use Java 1.5, which does not support getX/YOnScreen for MouseEvents.
I changed the code to:
        public void mouseDragged(MouseEvent e) {
            Point p = e.getPoint();
            SwingUtilities.convertPointToScreen(p, (Component) e.getSource());
            setLocation(p.x - clickx, p.y - clicky);And everything seems fine, until iI drag the popup out of the containing JFrame.
Then the disco starts.
If you can find the answer for this, tat would be great, but thanks anyway.