Yes, I did. I played around with it, but I can't see anything wrong in the way in which jPCT handles this. I think that this is either an issue with LWJGL's AWTGLCanvas or Jide is doing some hacky things to work its magic that interfere with what LWJGL expects from AWT/Swing.
I managed to configure jPCT in a way that at least the box shows up, but the colors were all white after an undock. I think what happens here, is that the GL context that is bound to the AWTGLCanvas by some magic is lost when Jide undocks the canvas. When talking to an invalid context, it often happens that some things still work while others fail. This is more a driver bug than a feature, because actually, rendering into an invalid context should give you no rendering at all.
If that's the issue, I think that recreating the FrameBuffer actually is the correct solution here.