When I am entering a game full screen, or changing it to full screen when in-game my mouse pointer is not hovering exactly where it looks like it is. For example, there are 5 buttons, one left, right, top, bottom and center. When I want to click the button center of the screen I hover a little above the button and click it, when I hover exactly on the button and click, nothing happens.
Now for the rest of the buttons, the more I move towards the sides or top/bottom the father away I have to point the mouse in order to click the button. For example, a button on the far right side of the screen. When I want to click this button on the far right of the screen, I have to point my mouse about 5 inches more to the right of the screen (And thus impossible) in order to activate this button.
I experience no difference when deactivating mouse acceleration or moving the pointer less fast.
Note: This does NOT happen in window mode.