Posted by gouessej on Feb 06, 2020; 9:27am
URL: https://forum.jogamp.org/Frame-with-transparent-background-tp4040332p4040337.html

Ok. Why not filling a bug report against Oracle Java?

In my humble opinion, it might be a limitation of Java2D OpenGL pipeline which was implemented earlier than the public API for translucent windows (the private API for that is a lot older, see AWTUtilities).

You claim that it's a simple case but it requires a lot of complicated source code to access to some native APIs to produce the expected behavior.

Have you tried "-Dsun.java2d.trace=log"? If so, what does it mention?

"-Dsun.java2d.opengl.fbobject=false"?