Although I've started to see this phenomenon after I upgraded my notebook from Oneiric to Precise, I'm not sure what is influencing.
(1st one of the following image) I dragged the window on right to the bottom. Then while I move around cursor, (2nd image) the window moves back to the top rim.


In this example the one on left remains at the bottom for some reason. And this can happen to other application window (e.g. Firefox, System Monitor etc.) Any idea??
(Environment) NVIDIA Driver version: 295.40, Gnome Classic (when using Ubuntu as a desktop style, this issue didn't occur)
