When replying to a thread, there's no indicator on the generated page of which thread the person is replying to. I think I've seen people accidentally reply to the "wrong" thread because they lost track.
Is it possible to see something like "Replying to: NNNNN thread" in the screen where a user is writing a post?
(I don't know how much such a feature would increase the burden on the server.)
You should see a screen below your Edit a Post textareawindow with the latest replies to the thread in it. Are you not seeing that information below the textarea??