When my keyboard and mouse are connected to my powerbook while sleeping (lid/screen closed), and I disconnect the apple USB keyboard with a mouse connected to the keyboard, the computer wakes up. Then, after a while, it goes to sleep again, since the lid/screen has been closed all the time. This is a bit annoying, since I usually disconnect the keyboard when I want to move the computer, and then I want the computer to be asleep. The strange thing is, that a few times, the computer didn't wake up when I disconnected the keyboard. Why does the computer wake up, when I disconnect the keyboard? And is it possible to prevent?