Everytime I try and play the campaign about fifteen minutes I lose the ability to move my mouse into the lower section of the map(the userbar area).... this has proved most frustrating.
Using Vista by any chance? I've had that exact same problem with Vista, but in another game (STALKER: Clear Sky), the cause was the theme used, Vista Aero, if I used the regular non-Aero theme the issue would go away. If that's your case try to disable the Aero theme for something else, or perhaps right-click the game's executable and check the "Disable desktop composition" box under the Compatibility tab (it could also help to use that trick if you're using Windows XP). Like Larkin said it's certainly not related to the A.I, I believe it would have been very well known and common enough by now had it been the case.