My 2012 Mac mini is connected to one monitor by the hdmi port, and to my 30" ACD using the Thunderbolt port. After the displays have been put to sleep, when I move the mouse to wake the computer up the monitor connected to the hdmi port wakes up just fine, but not the ACD connected to the thunderbolt port. The mini obviously *thinks* it's still connected to the ACD, which is my primary display, because the secondary monitor does not have a menu bar or dock etc., which *do* return to this smaller display when the ACD is disconnected. I have to unplug and replug the display from the Thunderbolt port and/or unplug and replug the power supply to the display. I'm running 10.8.4. Can anyone suggest any steps towards making this unnecessary?