User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:23.0) Gecko/20100101 Firefox/23.0 (Beta/Release) Build ID: 20130814063812 Steps to reproduce: Configure account to use IMAP server. (Server is Dovecot 2.1.15, mbox format) Create empty "folders only" folder. It appears in folder list. Attempt to delete folder (right click folder, choose "Delete") Actual results: Folder disappears from folder list, but restart Thunderbird, or close and reopen folder list, and folder reappears. Looking at an IMAP capture it appears that Thunderbird sends an "UNSUBSCRIBE" IMAP command for the folder, when it should really send "DELETE". Expected results: Thunderbird should send IMAP "DELETE" command, folder should get deleted from server, and disappear from folder list.