I'm using the latsest updates for both RB and biab. I had problems after defining a region, regenerating for only that region on one track. I just wanted to regenerate one measure of keyboard and it didn't work for about three attempts. Then it did, then it screwed up again. Others may want to check this scenario to see if it's just me, or a global problem. Try it a few times just to make sure it's solidly working for you.

Dan