This also happened to me. I am using Ubuntu 8.04. Switching System -> Preferences -> Appearences -> Visual effects from Normal to None fixes the problem. After switching back to normal, things are ok (for now).
This also happened to me. I am using Ubuntu 8.04. Switching System -> Preferences -> Appearences -> Visual effects from Normal to None fixes the problem. After switching back to normal, things are ok (for now).