Messages that the server saw earlier could easily be inserted partway up, right? We're talking about ~100ms most of the time; that's not going to cause you to miss messages.
Some chat service I use does this and it's confusing because I don't expect it. I check the last message to see if there's anything new, not necessarily the scrollback.
Basically, it triggers an annoying O(N) operation whenever it happens :)
Basically, it triggers an annoying O(N) operation whenever it happens :)