Moving between screens bug with VS2005

If Visual studio has focus, and you move onto a new screen something goes wrong and the mouse disappears until you move back onto the visual studio window. To correct the problem you have to click the mouse outside the window and move it. A selection box appears which you can then cancel. Basically, if you don't take focus off of VS2k5 first, the mouse pointer doesn't move between machines properly. I'm using Vista (Yeah, I know)