Why won't my macbook pro wake up when docked? I got a HengeDock for Christmas.  When I close my Macbook Pro and dock it to the external monitor, mouse, and keyboard, it will not wake up.  I move the mouse around and type on the keyboard, but it stays asleep.  Is this because I have a non-Apple monitor (I have a Sumsung -- highly rated by Consumer Reports).  Is something set incorrectly in my preferences?
According to Apple's kbase article HT3131, your machine must be plugged into power for clamshell mode to work.