Comment 7 for bug 940603

I think this is the same problem also happend while using chrome, but it covered nearly the complete display, the area below it is usable but you can't see what you are doing.
On pressing Super+S the workspace switcher showed, but every workspace had the white box (sorry forgot to make a screenshot)
Tried unity --replace via alt+f2 it resulted in some flashes, afterwards the desktop was completely unsuable, the launcher didn't react, alt+tab worked, but every window fas filled with the background of the desktop