When I am actually in game, my mouse cursor constantly floats to the left without that I am even touching the mouse. It still moves to the left when I actually use my mouse. If I move my mouse in the opposite direction the cursor floats to, the two movements are in conflict (so if I'll move my mouse slowly to the right the cursor will still go to the left, but at a slower speed, if I move my mouse to the right faster, I'll turn right, but at as slower speed than before. Also, I have the inverted mouse acceleration bug, so if I move my mouse to the right, I'll only be able to fight the float for about 45°).
youtube link: http://youtu.be/DiZkT9gSAVU (no audio, i am not moving my mouse)