Since I installed Gnome Shell (which I much prefer over Unity), there has been a small annoyance appearing on the right side of my screen. As you can see in the picture below, there is a blank few pixels on the right side of the screen. It goes away if I reload gnome-shell ("r" command), but obviously, I'd prefer that this is not necessary. I'm not sure what exactly is causing this, but was hoping someone might be able to help. I'm running Ubuntu 11.10 on a Lenovo Thinkpad Edge E420s