There are some tools for locking the cursor on fullscreen programs:
http://dualmonitortool.sourceforge.net/
Here's a forum post describing it for this exact purpose:
http://www.neowin.net/forum/topic/1146484-how-to-lock-your-mouse-inside-a-game-on-a-dual-monitor-setup/
Swapscreen.exe
Hey WootCandy,
I am aware that 3rd party solutions work but It's not the ideal solution though.
I use dual monitors and don't suffer from this problem, the game locks my mouse to the screen just fine both in borderless and in fullscreen.
In other words I can't replicate your bug.
Might be a hardware / windows settings specific problem
