FULL PRODUCT VERSION :
java version "1.6.0_13"
Java(TM) SE Runtime Environment (build 1.6.0_13-b03)
Java HotSpot(TM) Client VM (build 11.3-b02, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
When running a full screen JFrame (bounds matches screen size), opening a non opaque JPopupMenu overlapping a windows task bar (beneath the JFrame) will ignore the non opaqueness

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
- be sure to have a present windows task bar (not auto hiding)
- run attached source
- right click far from windows task bar and notice transparency of JPopupMenu
- right click to open JPopupMenu over task bar and notice lack of transparency of JPopupMenu

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
When opening a JPopupMenu in a full screen JFrame, I expected that the JPopupMenu could remain non opaque no matter where it is opened.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPopupMenu;

public class TransparencyPopupNearBorderTest {
    public static void main(String[] args) {
        final JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        final Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        System.out.println("Task bar insets at bottom: "
                + Toolkit.getDefaultToolkit().getScreenInsets(frame.getGraphicsConfiguration()).bottom);
        frame.setBounds(new Rectangle(screenSize));
        frame.setUndecorated(true);
        frame.setPreferredSize(screenSize);
        frame.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseReleased(MouseEvent e) {
                JPopupMenu popup = new JPopupMenu();
                popup.setOpaque(false);
                JLabel label = new JLabel("TRANSPARENT");
                label.setFont(new Font("Helvetica", Font.PLAIN, 42));
                popup.add(label);
                popup.show(frame, e.getX(), e.getY());
                System.out.println("popup bottom edge is "
                        + (screenSize.height - e.getY() - popup.getPreferredSize().height) + " from screen bottom");
            }
        });
        frame.getContentPane().setBackground(Color.BLUE);
        frame.pack();
        frame.setVisible(true);
    }
}

---------- END SOURCE ----------