I have seen this some time ago too! Usually with animated graphics, you have a continous redraw loop. Under some circumstances (maybe driver, os dependent) a popup menu triggers some kind of clear, visible as flickering bg colour between the frames. If you do all your drawing inside paintGL() as you should, and still experience this problems, it is definitely some lwjgl fault as I would say. For the lwjgl maintainers I can propose to try out some less potent GPUs (onboard's) on linux machines, where I encountered this error.