It's not a matter of delaying. If you opened the thread any time BEFORE that previous message was posted to the database, by it's author clicking the "REPLY" button, you won't see it until you close the thread, then re-open it. I've VERY rarely, if ever, seen a forum that works any other way. Making everyone's display update instantly would make the entire forum, and the database itself, massively slower, and more bandwidth-intensive.