I upgraded to Lion yesterday, then installed iTunes 10.4. Now, whenever the Apple TV 2 is playing anything (video or audio streamed from the iMac) I cannot get the iMac to keep its screen turned off. I press CTRL-Shift-Eject and the screen goes off, but comes back on within a few seconds. If I stop the Apple TV from playing and turn the iMac screen off, it stays off. But if I start playing content on the Apple TV at any point then the iMac will come back to life within a few seconds. I'm only turning the screen off, not attempting to put the iMac into sleep mode or anything. This has worked since I got the Apple TV last November with no troubles, it is only doing this since yesterday. Any suggestions?