Comment 8 for bug 66652

Okay, I need to ask a favour.

In bug #67443 , Thom Pischke (sorry I just called you by your last name, by the way, if you're reading this!) fixed a problem which I had a hunch was related to this one, in which progress bars were not displaying.
The fix for that also managed to fix this!

So, I ask that, if you are encountering this problem, you please try adjusting your DefaultDepth in /etc/X11/xorg.conf. Try lowering it to 16 first, and then restart X and see if anything has changed.
Hopefully it has, in which case both this bug and #67443 can probably be considered the same issue...
Perhaps a feature request could be filed: Ubuntu could check if current graphics options are suited to the driver in use, and pop up a warning if they are not. That way, if someone ends up with the wrong DefaultDepth, they can find and fix the problem immediately. (Assuming that sort of check is possible).