FULL PRODUCT VERSION :
java version "1.6.0_11"
Java(TM) SE Runtime Environment (build 1.6.0_11-b03)
Java HotSpot(TM) Client VM (build 11.0-b16, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Ubuntu Hardy Heron, Linux hostname 2.6.24-22-generic #1 SMP Mon Nov 24 18:32:42 UTC 2008 i686 GNU/Linux


EXTRA RELEVANT SYSTEM CONFIGURATION :
Non-3D desktop, ATI graphics (both open source and binary X11 produce same result).

A DESCRIPTION OF THE PROBLEM :
Normally a menu can be invoked by pressing down on the mouse, navigating to the desired menu item or submenu item, and then releasing the mouse. This has been the default behavior for all prior versions of the JDK. With every build of 1.6 encountered on Linux, this silently fails to invoke the menu action. One must peform a full click to lower the menu, then float to the menu item or submenu item and click again to invoke the action.
The small menu demo program here can reproduce the result:
http://www.onjava.com/pub/a/onjava/excerpt/swing_14/index1.html
However, the menus on SwingSet2 work properly.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Download and compile the IntroExample.java program here:
http://www.onjava.com/pub/a/onjava/excerpt/swing_14/index1.html

Press down the mouse to lower a menu, navigate to a menu item or submenu item and release the mouse. The menu action is not fired. To cause the menu actions to fire, one must click once to lower the menu, then navigate to the menu item or submenu item and click again.



EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The menu item action should fire when the mouse is released on the menu item.
ACTUAL -
The menu disappears as if the action were fired, but no action occurs.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
No error messages.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
Please refer to the IntroExample.java program here:
http://www.onjava.com/pub/a/onjava/excerpt/swing_14/index1.html
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
  To workaround, use single mouse clicks to open a menu and then another click to choose the menu item.