One person may now leave and rejoin and collabedit will still work.

Collabedit now always starts by sending the shadow from one person to the other. This case on a rejoin the saved shadow will be sent to the new user.
Can we not have this log here? Collabedit messages come in once per second right now (4 times per second in my UI branch), which means our log will be filled with nothing but collabedit messages. What's more is that if the text in the box is really large, the message field will be huge too and take up a ton of space