I've actually seen this with all my full screen applications on dual screens, when the resolution of the game is not the same as the resolution of my desktop. 

Have you been able to get any other applications to do a full screen @ non-desktop resolution that doesn't do this? I haven't, and if you've figured out how, please tell me!

As a suggestion, try setting elemental's resolution to be the same as your desktop resolution.  When I do that, everything works fine.

Good Luck.