I cannot speak to why TB shows what appears to be the old connection, but I feel strongly that it is not connecting there, because you don't have an account there anymore. The folders are showing the proper messages, so all is working as desired. The problem of IMAP sometimes having trouble saving to sent folder is due largely (from my experience) to network issues. Consider, it must first send the message to recipient and then send the same message to your IMAP folder. I recently had a low-end IMAP account and I sidestepped the issue by defining my Sent folder locally. Not desirable, but it avoided the problem and I soon quit that account.