And it looks like nobody has fixed yet... I've also found that topic from 2006 and then I got here. How it's possible that a bug still unsolved for almost 10 years? While that miracle happens I've solved the problem by myself using this simple piece of code: Func myMouseMove($x,$y,$speed=0)
if $x<0 Then $x-=1
if $y<0 Then $y-=1
MouseMove($x,$y,$speed)
EndFunc
It's very simple. When you move the cursor to a pixel position which is negative, the MouseMove() function performs the movement with an offset of +1px. That's why this only happens when you move the mouse on a screen above or on the left of the main screen. So you only have to substract 1px if you want to move the cursor to a negative pixel.