FULL PRODUCT VERSION :
java version "1.6.0-beta2"
Java(TM) SE Runtime Environment (build 1.6.0-beta2-b76)
Java HotSpot(TM) Client VM (build 1.6.0-beta2-b76, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
X server: Solaris 10. X Client: Windows 2000 running latest CygWin/X library

EXTRA RELEVANT SYSTEM CONFIGURATION :
JDK needs to use XToolkit for rendering to reproduce this.
setenv AWT_TOOLKIT XToolkit

A DESCRIPTION OF THE PROBLEM :
Given a simple swing app that has either a main menu with a dropdown, or a popup menu, run the app via X, rendered onto a client workstation using XToolkit renderer.

Try to select an item on the dropdown menu by clicking on the menu to get the pull down, then clicking on the item. When you release the mouse after getting the drop down, the menu does not stick, it disappears, making it impossible to use the mouse to select the item with the second click.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Swing app with JMenu that has a drop down with at least one item (or a popup menu access via right mouse click - same problem).
2. setenv AWT_TOOLKIT XToolkit to force use of XToolkit (I heard this would be a mustang default on Solaris, but it does not seem to be in this case.)
3. Run app, rendered onto a second X workstation behaving as client. (I used latest Cygwin/X on Windows/2000 over DSL connection) It does not matter whether lbx_proxy is used or not - I reproduced problem both ways.
4. Click the main menu (and release the mouse button) to get the drop down menu to appear.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Menu would stay visible allowing user to select the menu item they wanted.
ACTUAL -
Menu disappears making it impossible to select anything via the mouse.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
Just create a JFrame w/ menubar, one pulldown w/ one or two items on the pulldown.
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Press and hold the mouse to get the menu to appear. Then while holding the mouse button down, use the arrow keys on the keyboard to select the item you want, then hit enter to select it. The work around is incredibly annoying but it works.

Release Regression From : 5.0u6
The above release value was the last known release where this
bug was not reproducible. Since then there has been a regression.