Move a screen by the specified amount in X/Y direction. The
resolution is always the screen resolution.
INPUTS
screen
Move this screen
dx
Move it by this amount along the X axis (> 0 to the right,
< 0 to the left).
dy
Move it by this amount along the Y axis (> 0 down, < 0 up)
RESULT
NOTES
Depending on other restrictions, the screen may not move as far
as specified. It will move as far as possible and you can check
LeftEdge and TopEdge of the sceen to see how far it got.