I'm using Version 12.1.1 (12.1.1.26821) on Mac OS X 10.7.5. I bought Mass Effect yesterday through Steam, and I am seeing the mouse issue described in multiple posts below (can't pan across full width of screen).
I see that Mass Effect was rated Gold for Mac as of 12.0.0. The next-most-recent thread claims the bug was thought fixed but isn't as of mid-2012. What's the current status? Is there a known work-around for this issue?