In TWS, you bug multiple targets. You can "lock" one by pressing TAB on one twice.(Bugging them, then locking them) The reason they are not "Locked" when you push TAB once (In TWS) is because the radar is tracking them, but not "following" them so to speak, because it needs to continue to search for targets. As a result, you must continue to keep adjusting the radar so that the target stays in the cone. (Or you lose lock) When you "Lock" a target, the radar tracks and follows the target. you no longer have to adjust the radar elevation and such, but you cannot track multiple targets because the radar is focused on one target.