Niche issue discovered:
Visit IP.Chat
Open IP.Chat in a popup, but leave the main window on IP.Chat as well.
Post in the popup window
Bug: Those posts do not display in the main window
Reason for this is we verify the user id so that your messages, which are inserted locally automatically as you post them, aren't re-inserted when they download from the server. Not sure how we could approach this safely, but as no one is likely to run into it in real world usage (and a simple page refresh fixes the issue in the main window), I don't want to break existing functionality to resolve this issue right now.