10.6 Wake from screen saver bug

I have my MacBook Pro set up to require a password when I try to wake my laptop, or use it after the screensaver has come on.

This morning I went to use the machine and it was not asleep, I could tell from the status of the light, and the screen was lit, but there was no screensaver, and no security dialog asking me to log in. No manner of keyboard tapping, pressing ESC, etc helped.

I logged in remotely over SSH and killed the screensaver process, but that didn’t help either.

I then unplugged the mouse from the laptop and suddenly the machine came alive, asking me to log in.