When you add comments to lines in a diff, they're sorted by the order in which they're made by the reviewer, not in the order in which they appear in the diff. In many cases this is undesirable (e.g. for the reviewee who's trying to make requested adjustments, it's annoying to have to jump from file #1 to file #2 and back to file #1). I think sorting by location would be more reasonable. (Being able to manually rearrange the order in which comments appear would be great too, but maybe overkill.)
