Multiplicity and MMOs

Having an ongoing issue with Multiplicity and playing MMOs.  I like to dual box and for the most part this program is fantastic in allowing me to control two guys, but every time I play for more than a few minutes my primary display's right "look" mouse stops working.  I can still use the keys to look or turn around, but my right mouse button look/move stops.  On the secondary machine everything works great! 

A search on the web reveals this is an ongoing problem.  I used this program 7 years ago with Everquest II and remember having a similar issue.  I am using the latest version of Multiplicity and Windows 7 on both machines.

Any ideas or help?

Cheers