FULL PRODUCT VERSION :
java version "1.6.0_10-beta"
Java(TM) SE Runtime Environment (build 1.6.0_10-beta-b23)
Java HotSpot(TM) Server VM (build 11.0-b11, mixed mode)
ADDITIONAL OS VERSION INFORMATION :
Linux penguin-splendor 2.6.24-17-generic #1 SMP Thu May 1 14:31:33 UTC 2008 i686 GNU/Linux
A DESCRIPTION OF THE PROBLEM :
When "Enable the per-pixel translucency effect" is selected in the demo available at,
The translucent frame completely disappears. However, if this option is not selected, the translucent window is visible and normal translucency works fine. Due to this, the "Paint Gradient" option does not work well too.
The demo runs perfectly well on Windows platforms. I'm sorry that I'm unable to provide my own code to demonstrate the bug as I do not want to install a Beta JDK for various reasons.
But I decided that it should be due to a bug in JRE because the same demo runs well on Windows. It is really disheartening to see a brand new exciting feature having a platform specific bug.
STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Launch the demo at http://java.sun.com/developer/technicalArticles/GUI/translucent_shaped_windows/#Demo
With compiz enabled on Ubuntu 8.04, select "Enable the per-pixel translucency effect" and "Paint gradient" check boxes. Then click on "Display the frame" button.
EXPECTED VERSUS ACTUAL BEHAVIOR :
A translucent window with a gradient of 100% opacity at one corner and 0% opacity on the other.
The translucent window was not visible. However, a taskbar entry is visible with "Java" as title.
This bug can be reproduced always.