>>What I'm saying is that, after I read all the messages in the list and go away, the next time I log in I may not see all the messages posted since what was shown in the frame when I disconnected normally from my last session.

FWIW, I have this problem, too. I don't think I ever miss the opening message of a new thread, but I have missed messages where a thread 'branches' due to multiple people responding to the same message.

Since I've recently become a PUTM, this is less of an issue as I can 'View Entire Thread' and follow up on any messages I may have missed.