let me rephrase that. well for me it was the mouse movement detection, in a smaller window there is no aiming issue, the aim seeem to be scaled along the window width. if the window is wide, you need even more space before the aim-point begins to turn, and likewise in a thinner window, it just needs halfway of the whole background picture with to aim all across.
so on a maxed window, if i want to aim to the right side, it just barely reaches the middle of the whole aiming area