My favored class isn't class 0 (because at character creation time, I specifically chose a dip into a non-favored class first). There's an explicit field for favored class; but that's not the class that's shown at the top of the character sheet. I would think that the class at the top of the character sheet ought to be either the favored class, or freeform (e.g., "Fighter/Thief") and unconnected to any other class designation?