Hi Philippe,
Thanks for sharing the solution to your problem! I can't seem to duplicate it, though
When I take the simple JOGL 2 example at
https://jogamp.org/wiki/index.php/Using_JOGL_in_AWT_SWT_and_Swing, and set it up in NetBeans as shown at
https://jogamp.org/wiki/index.php/Setting_up_a_JogAmp_project_in_your_favorite_IDE, it seems to work fine in NetBeans 7. I updated my NetBeans version this morning to make sure.
I ran my test on Windows 7 64-bit -- what platform are you running on? Maybe there's a platform-specific or project-specific problem.