I just upgraded my Ratel Performance (ratp1) to 13.04 and I've started having a problem with minimizing windows. It is sporadic behavior so I still haven't isolated the cause. Sometimes, when I minimize a window, a jumbled remnant of the window contents are left on the desktop background. There doesn't seem to be any instability caused by the issue - I can still operate everything just fine, but my background becomes completely filled with whatever windows I have had open, even if I have closed everything. It's as if the desktop background is being overridden by these minimized windows.
Here's an image of the most recent occurrence. All windows are minimized and this view should be a clean, unobstructed desktop:
Screenshot from 2013-06-22 09:28:08.jpg
I am running the stock Ratel Nvidia card and I suspect that is the issue, but I don't know how to go about troubleshooting any further and couldn't find any information in the forums. Has this issue been encountered before?