A new regression

[Mike Hearn]

> The problem is that the app uses OpenGL for painting, and OpenGL
> doesn't support the IncludeInferiors clipping mode. Fixing that
> properly will require getting rid of X windows for child windows, but
> in the meantime I have added a workaround that should work in most
> cases.

For those following along, translated that means: fix that works all the 
time blocks on the window management 'rewrite' which means we use X 
windows only for toplevels. Last I heard this rewrite was about 2-3 
months away from completion but obviously it's not a fixed thing and 
could easily take longer.

The reason it's being taken slowly is exactly so these sort of 
regressions can be shaken out. In the absence of branching it's the only 
way.

thanks -mike