Okay, this may be a dumb question; bear with me for a second. I decided to change the keyboard commands for Expose tonight. For the F keys, I could pick anything from F1-F13. Excellent, I thought -- I'll pick F11 / F12 / F13! Problem: My PB (15" AlBook, Rev C) has no F13 button. So, I was wondering: is there a button that serves as F13, or is it there for people with external keyboards (do those have F13s)? Yes, possibly a dumb question, but I thought it was odd that I was afforded the F13 option when there's apparently no F13!