so all this talk about image retention has kinda got me worried but its better to be safe than sorry on my 2012 rMBP 15", i have the display sleep enabled to 5 minutes. i usually leave my laptop pretty dim to conserve battery (2 or 3 bars of display light). one day i noticed that after my display went to sleep, i noticed the display didnt completely sleep. i'm not sure if this is how its suppose to be but what i saw was the window that was left open right before the sleep. is this something i should be worried about or is it completely normal for the display to not completely go black?