Sorry, I was in a rush when I wrote my original reply. I realized about ten minutes later I was wrong.
There is a bug in 1.4.2 where focus changes in JInternalFrames cause addNotify / removeNotify to be called on the contained components. This isn’t what you’re seeing.
The GLJPanel has a backing pbuffer which is originally 256x256 and is resized in the X and Y axes by powers of two when the GLJPanel becomes larger than the pbuffer. Is this the effect you’re seeing, or are you seeing continuous calls to init() while you resize it? You should be able to reduce this effect by making the GLJPanel about as large as you expect it to become. You could also work around it by making it a large size for one frame and then immediately resizing it to a smaller size. Do these suggestions help?