Really want to edit comments in the topic for N-minutes (think 2-3 minutes, not more) from the date of dispatch, but not later than someone wants to answer it. Ie when you click "reply" — Ajax-request edit the previous comment is blocked, and even if the author has started editing — it soobshaet, sorry, excellent, you're late. Need happens often — see an error, the parser is a goof and he needs help, etc.
Now I do not know, before the preview of the commentary do not coincide with its final display — they should be 100% identical