Well i'm no expert at flash and actionscript, but to my knowledge the flash application cannot detect whether a mouse goes off the window or not. Because when you take your mouse away from the window it just assumes the mouse is still in the last recorded position in the window. A good way to visually show this is by using a custom cursor.
However, you could make a script that detects if the mouse is right on the edges of the scree, like a few pixels away from the borders of the application. This surely should have the same effect as it being off-window.
But mabye i'm wrong; just trying to help.
saltovergray
i hate that gif. it's very annoying.