I assigned the "Display Off' iDrive menu item to one of my steering wheel multi-function buttons. Not sure why I did, I was waiting in a queue to get on a ferry and was bored. I've noticed though, that it doesn't actually turn the display off at all. You can see it's still backlit and using as much power as it was before the Display Off was selected. I made a little youtube video to demonstrate it. I told you I was bored - waiting an hour in a queue in my car :-(

 

This isn't something I imagine they'll "fix" in a software update -- I think this is the way they designed it to work. Yes, it seems silly, etc. but they probably didn't want the display to become completely disabled (turned off) in case a warning message was necessary.

Sure there are probably other ways of automatically turning the screen back on if a warning comes up, etc. but I can only guess that the newer versions of iDrive may have that function, not newer updates to the versions we have in the E60...