FULL PRODUCT VERSION :
java version "1.6.0_02"
Java(TM) SE Runtime Environment (build 1.6.0_02-b05)
Java HotSpot(TM) Server VM (build 1.6.0_02-b05, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux curium 2.6.20-1.2948.fc6 #1 SMP Fri Apr 27 19:18:54 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux

(Also observed under other Linux versions)

EXTRA RELEVANT SYSTEM CONFIGURATION :
GUI displayed using a remote X server: XMing, running on Windows XP, in "multiwindow" mode (rootless, with native window decoration and management).

A DESCRIPTION OF THE PROBLEM :
When using Swing components that bring up child windows, such as context menus and combo boxes, in the setup described above, mouse events are not delivered correctly. If the containing, top-level window is left in its original location, components behave as expected. However, if the top-level window is moved, pop-ups exhibit incorrect behaviour in two forms. In some cases, they appear relative to the original location of the window, regardless of its current location. In others, the pop-up window is displayed relative to the current location, but receives mouse events in the area it would have been in had the top-level window not been moved. The latter case makes the component essentially unusable.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run an application that uses combo boxes or menus (such as the provided test case), using the XMing server in multiwindow mode (we have also had reports of the same problem using the Cygwin X server in multiwindow mode). Bring up a menu and select something. Move the top-level window containing the menu bar, combo box or other originating component. Bring up a menu and select something.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Both attempts to select an item from the menu should work normally.
ACTUAL -
The first attempt works normally. In the second case, either the menu will appear in the wrong place, or will appear in the correct location but the "sensitive" area in which it receives mouse events will be relative to the original, not the current, location of the top-level window.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.*;

class SwingTest
{
  public static void main(String[] args)
  {
    JFrame frame = new JFrame("Test");

    String[] strings = { "One", "Two", "Three", "Four" };
    frame.getContentPane().add(new JComboBox(strings));

    frame.pack();
    frame.setVisible(true);
  }
}


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

CUSTOMER SUBMITTED WORKAROUND :
When using MToolkit (e.g., by setting the environment variable AWT_TOOLKIT=MToolkit), the problem does not occur.