Well, I use a monitor but it's not 1080p. I installed 10.3.5 yesterday and now my MBP won't run in clamshell. I can get the external monitor to mirror the MBP display, but the MBP won't go to sleep when I shut the lid. If I restart it with the lid shut, the MBP display still comes on.
I had this problem before, but it was hardware related and got it fixed. This time I'm 95% sure it's the software because a) it was fine before the update, and b) everything works as it should when I load up bootcamp.