Confirming this one on Ubuntu 12.04 as of now, with proposed enabled and all current updates applied. Using proprietary nvidia-driver. Grab a window and juggle it around, especially hitting some maximization spots like the top bar or left/right edges, and the cursor can easilly become "detached" from title bar while grabbing/moving. So the mouse cursor visually grabs into thin air while still having a hold of the window.
Confirming this one on Ubuntu 12.04 as of now, with proposed enabled and all current updates applied. Using proprietary nvidia-driver. Grab a window and juggle it around, especially hitting some maximization spots like the top bar or left/right edges, and the cursor can easilly become "detached" from title bar while grabbing/moving. So the mouse cursor visually grabs into thin air while still having a hold of the window.