When Panning or Orbiting, cursor jumps to primary monitor.

[moogoo2]

Whenever I try to pan or orbit in any viewport using my middle mouse button,  my cursor jumps to the equivalent coordinates on my primary monitor.  This causes the pan operation to move my camera the full distance from the viewport to the other monitor. I completely lose track of where the geometry is, and have to alt+z to get it back.

Obviously, if the viewport is on the primary screen, everything is okey dokey, and this is only an issue on my other monitor.

Any ideas? 

I'm running Max 2012, SP2 with the latest update.