That's what happens when you work on too many things at the same time. The mind wanders, and then so do the fingers.
One of the most embarrasing aspects of my life is my typing method, which involves a lot of looking at the keyboard. When my coworkers wander by, I try and look at the screen. I don't know what the hell is wrong with me. I guess it comes from learning typing as a programmer.
Note to self: Learn to type like a human.