I don't know whether this has been in other releases, because I only used the Gnome System Monitor after installing the alpha7 release.
The first issue I had was moving a file between two Rox-FIler windows, and the "Move" dialog box left a border and titlebar artifact. btw: this has not repeated. I tried the Rox Sydtem montor, and there was no trace of it. I then opened gTop using the BB menu. Still no trace. Then I tried shutting down gTop. With both artifacts, even xKill wouldn't work. I had to use the "Restart" option in the menu to get rid of the frame. I've tried to replicate the Rox problem with no success. The gTop problem works every time. As I said, alpha7 release. This is on a Mandrake 8.2 box (which I may be swapping to Debian tonight. WooHoo!) I'll enter this into the bug-tracker in a couple of hours. Just about to go to a LUG, and found this problem. Keep up the great work Sean, and thank you to all the other contributers too. Neverness -- Of all the things you can accomplish by screwing up your face and swearing into a darkened room, sleep is not one of them.
