I did a clean install of Ubuntu 11.10 recently. Every so often, Grab Handles will appear on the active window. Sometimes they simply disappear after a few seconds without causing me any problems.
Other times, the mouse appears already grabbing the window (like when you grab the center handle) and the mouse and the window will shake erratically for a few moments. In this case, I lose control over the mouse until the grab handles fade out a few seconds later. This occurs multiple times a day, maybe once every hour or two. The oddest thing about it is that I don't have Grab Handles enabled:
For reference, this is an Asus G53SW laptop with a Core i7, GeForce GTX 460M and 6 GB of RAM. Any ideas?