Rob, I haven't been able to reproduce your problem here and have double checked module source without any luck.
I would try adding a PollSystem at the same point you are flushing the graphics pipe with GrabPixmap. If that fails, you might want to consider sending me a build to see if I can reproduce your problem here.
I would try adding a PollSystem at the same point you are flushing the graphics pipe with GrabPixmap. If that fails, you might want to consider sending me a build to see if I can reproduce your problem here.