Oops, forgot about that.

(Actually, it was 2nd pass. Am I really the only person to have used it on these sets?

Just noticed this...
"along with menus for audio and chapter selection."
Actually, the audio selection is forced when you go into the commentary menus. It works behind the scenes (and at this point, you have to manually select the 5.1 during the movie. It's there just as a curiosity.)