OK, thanks, that clears that up then. So foes still can't stream by the fighter after the lead one draws the hit, but shifting by kobolds can be done safely after one draws the Combat Challenge. Hmm.
SOooo, that means that the fighter cannot stop someone from shifting, even if he hits 'em, because it's not an opportunity attack (unless you read the "move provoked attack" line of Combat Superiority VERY broadly).
Good, I think that would free up combats a bit. It wouldn't have affected our game much because the kobolds weren't serious threats and the hobgoblin warriors wound up seperated, but it's nice to know they could have shifted a little more freely.