Comment 2 for bug 774060

I think I know why this is. In Unity, there seems to be a 1-pixel gap at the right and bottom of the screen that the pointer cannot pass into. When you drag a window to the right (or indeed bottom, if you have it enabled to do something) of the screen, there is one pixel that is "missing" and is not considered in the animation, so the animation doesn't complete. This pixel border also affects other things: http://askubuntu.com/questions/38386/unity-1-pixel-border-affects-compiz-button-binding-shortcuts