Created attachment 644923 [details] [diff] [review]
This is because when a conversation is closed, the code attempting to update the tab title calls Services.conversations.getUIConversations() which still returns the conversation that has just been closed, and the isChat getter of that already closed conversation doesn't work because _currentTargetId has already been deleted.
An easy fix is to just send the ui-conversation-closed notification a little bit later so that the closed conversation isn't listed in the results of getUIConversations.
Comment on attachment 644923 [details] [diff] [review]
Yeah, I really think we want to have this on aurora/beta.
Backed out of comm-beta since we landed on a SeaMonkey relbranch (oops).
Re-landed on comm-beta as: https://hg.mozilla.org/releases/comm-beta/rev/784670aca2d2