crossfire glitch?

I've got a computer with crossfire that I've just recently put together. I have three monitors plugged into it, and am attempting to rig the thing so that when crossfire is off, and the two-ports-per-card (total of 4) are all usable, my three monitors are all a giant desktop, and when I flip crossfire on, it only runs the main monitor and lets the other two go black.

This has worked quite nicely, but for some reason it likes to make one of the non-primary monitors fire up (the right one for some reason) rather than the main one when I flip crossfire on. It happens randomly, which is wierd because the primary one is on the primary port of the primary card, so there's no reason I could think of that it would randomly pick the other card as the primary.

I dunno, I know this is kinda specific, but I'm wondering if anyone else has run into this with a crossfire setup. Any tips?