I just noticed something weird:
if you run an AGS game, and move its window through external means (that is, not by dragging the title bar, but e.g. by using the "Tile Horizontally" button from your task bar) the mouse cursor screws up (the AGS cursor appears in a different position than the windows cursor). It's kind of hard to explain but try it some time :)
Hehe, that is rather strange! Considering the obscurity of it, though, I'm not going to spend any time investigating it right now.