Whenever I'm at home, I use my MacBook with an external keyboard, mouse and monitor. I usually just run it in clamshell mode. FOr some reason I am unable to wake up my computer when the power adapter is not connected. Is this normal? I am also unable to use my computer when the power adapter is unplugged. For example, if I unplug the power adapter while it's on, the computer will automatically go to sleep. Is this supposed to happen?