Joining and then leaving a chat room throws a console error.

[startupandrew]

Try joining a chatroom, and then clicking the "x". You won't leave the chat room, and you'll get a console error.

[kidlab]

I had the same issue, walk through the code, I think the problem is at this line

this._chat.getRoom(invitation.toRoomId, function(room) {
  self.attachTab(invitation.toRoomId, room.name);
});

There's no property toRoomId, it should be roomId.