When looking through your Comments, how do you know which ones you've already replied to?

I see no indication on any of the Comments in my list as to which ones I’ve already replied to! I’d hate to look like an “idiot” and reply to the same Comment twice!

I think that there should be some sort of feature to mark those Comments which have already been replied to. If it exists, I sure don’t see it!

IS there such a feature? If not, I think that one should be added!