I dunno, I had this problem daily 1-3x an hour before, I was running Keyclone with PIP/Maximizer and 5 wow windows spread out over 3 monitors so I could see them all.

Last week I switched to Octopus, and collapsed all my WoW windows so they are right on top of each other. I keep one alt on my 2nd monitor, since hes usually the herbalist so I can see them on the map and grab em.

Since I switched, I haven't seen the problem once. ever. I don't know if its because I have all my WoW windows on top of each other or because of Octopus or because God loves me, but just for what its worth.

My FPS also jumped up significantly since I no longer show all WoW windows on screen, and now I just bind F1-F5 to hotswap between my wow windows (and also F1-F5 is set to /focus <person> and /promote <person>), its simplified my MBing a great deal. Really ask yourself whether you need to see all your toons on screen at once.