Bert,

> > Well, not really. Looking at WonderlandCameraMorph>>drawSimulatedOn:
> > should explain what's going on. If the renderer is an 
> > overlay renderer (e.g., rendering to some OS window) then we dump
> > it if we go into simulated mode.
> 
> I just removed the dumping and all is fine.
[...]
> It works fine even when dragged!

I'm somewhat surprised to hear this. I would've suspected that X doesn't
allow parent windows to draw within child windows without setting up some
specifics. If it's generally true that the parent window can in fact draw in
the child area you could very simply make glIsOverlayRenderer() return false
- the entire purpose of this method is to figure out if Squeak can or can
not draw on top of that context.

Cheers,
  - Andreas