yeah I’ve had this FP with MBAM as well, just send it to your ignore list, no need to worry at all. Their forums is full of posts about it and as David said, the active desktop has got nothing to do with icons or your desktop being active, it’s about the implementation of web elements on it…feature was never used (by me) in XP…thought it was abandoned completely.
I guess the registry is still a bit of an archaic structure, there are probably many redundant settings. It would I guess be a massive task to start from square on in the registry and as far as I’m aware the win7 registry is even bigger than Vista.