I'm not sure if there's anything I can do about this, but thought I'd ask. I have a Mac Pro (Early 2009) running Lion, with a Radeon 5870, and 2 monitors. Both monitors are connected to the 5870 with HDMI to Mini Displayport convertors (Different brands for the convertors). For the most part, I use the secondary monitor for iTunes, iCal, Twitter, etc... Anytime I turn off that monitor, even if for just a minute, then turn it back on, all app windows that were placed over on the secondary monitor get moved back over the primary. It's not a deal breaker, but it's a bit unfun to reposition all of these apps several times a week. Is this a common issue? If not, is there a silly fix I'm not realizing?