I have the screen off, and every 15 or 20 minutes, the screen will turn back on to the lock screen until the sleep timer goes off again. How can I figure out what this is? I thought it was a lock widget updating (Agenda Widget) but even with no lock widgets it sometimes comes back on. I thought it was location services from some app (Prey, etc.) because sometimes immediately upon wake there's a little location notification icon but I turned that off and no help. Sometimes there's a Gmail icon, but I've tested it where I clear all my notifications, and then on my laptop, I send an email and I get the audio notification, but no wakeup. I'm stumped and it's quite annoying, can anybody help?