Dragging a window from one screen to another: Window loses reference to mouse

[Kalsan]

I have two screens, the left one has resolution of 1280x1024, the right one 1280x800. I've set them up so that they're on a line on their bottom and the left screen is "higher" than the right one. Between them there's a height difference on the top edge, and the mouse stops there. When I move it down and to the right, it keeps running straight down until it reaches the height of the right screen, than it enters the right screen.
The problem: When I drag a window from the left screen to the right one, the mouse stops correctly on the edge that marks the difference between the screens, however, its coordinates relative to the window title bar I'm dragging get somehow messed up. So when I enter the right screen, the window is as far away from the mouse as I dragged it against the border merking the height difference. Please see the attached video, as this bug is really hard to explain.