We use a GLJPanel. I'm running on a Mac laptop with Retina display, and an external non-Retina display. When I put my GLJPanel on the external display and close the laptop cover, everything from the laptop display moves over to the external one. The GLJPanel gets displayed.
When I open the cover again, I get a reshape (twice as big as if the GLJPanel were on the Retina display) and then a display, then it gets reshaped back to its original size. Sometimes I see a flash of junk drawn in the GLJPanel.
When I turn on debug logs, I see that setNewPixelScale for the GLJPanel, which is why it gets reshaped temporarily to twice the size. I don't know why this happens.
I may be able to investigate further in a couple of weeks, but I thought I'd report it in the meantime. I will try with a short standalone JOGL program.