Version: (using KDE KDE 4.0.0) Installed from: Ubuntu Packages OS: Linux When trying to shutdown the computer, the gray area doesn't cover all the screen. Anyway it's possible to shut down the computer correctly. I made a (low resolution, I'm sorry) video to show the problem: http://www.youtube.com/watch?v=GYkjKST7x_w
Are you sure your are using 4.0.0? I think I have solved this bug a little before the 4.0.0 tagging...
Quite sure that I have fixed this one some time ago; closing due to missing answer.