From https://bugzilla.mozilla.org/show_bug.cgi?id=921050#c26 as a followup to the outbox user story: outbox.js' sendMessage treats FooAccount.sendMessage as a conceptually atomic thing. But for CompositeAccount with ImapAccount there's our under-the-hood call to ImapAccount.saveSentMessage which will schedule a non-persisted appendMessage operation for non-gmail IMAP accounts. We don't wait for that to complete. I think it would be ideal if we were able to track the send status so that there's an additional state representing "sent but not yet appended to the server". Right now our failure mode is that we may fail to append the message.

Firefox OS is not being worked on