Open Radar

 
Summary:
When I used my 15" MacBook Pro (running 10.6.8) to run my iMac 27", Late 2009 as an external monitor, and I've worked long enough on the MacBook (and been idle long enough on the iMac) to have put the iMac into Display sleep, when I disconnect the MacBook Pro, the iMac display remains on, but black. Sometimes there's a mouse arrow in the upper left, depending on how rdar://10488440 feels today. It will never go into display sleep if I leave it, and must "wake" it into normal operation before it will decide to then (after the time expires again) go back to display sleep.

Steps to Reproduce:
1) Boot iMac 27".
2) Log in as a user with a 10 minute display sleep, but never computer sleep.
3) Connect MacBook Pro and work for 15 minutes.
4) Disconnect MacBook Pro

Expected Results:
Display turns off.

Actual Results:
Display remains on, but is black, and sometimes there is a cursor in the upper left corner.

Regression:
I honestly don't remember this happening in 10.6.x, but I don't have a repro case any more.

Notes:
I don't have good data on this, but sometimes, even after working _well_ after the display sleep should have kicked in and based on the other security settings, I should require putting in my username and password to use the machine, I disconnect the MacBook Pro and the display is neither asleep nor blank – I am in my normal login session!