User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:1.9.0.11) Gecko/2009060215 Firefox/3.0.11 Build Identifier: Thunderbird 2.0.0.0 Bug 236030 has been marked as a duplicate of (eventually) 301084, which has been marked fixed. But only the "save reply to current folder" has been implemented; this is to reopen the "but if it is the INBOX to Sent" part. Sorry, I don't know how to reopen a third-party bug (if this is possible), which would be easier than submitting a new one. But I'll put a comment there. Reproducible: Always

This bug also in Seamonkey 2.7 The sent email ends up in the Inbox, rather than the sent folder as specified in the settings.