Just a quick question - I am currently using the 2011 Air in Clamshell mode on my U2410. Whenever the Air sleeps the display, the monitor turns black with the backlighting still on. This is rather strange, since the U2410 should go into standby when it stops receiving a signal. Is the Air still 'using' the monitor when it sleeps the display? Are there any settings that can be toggled on the Air?