I just looked at my inbox in Icedove, and noticed that an old thread
had been moved to the head of the chronological listing--as if it had
new messages..., but there were no new messages in that thread.
Not visible in Icedove, not in the inbox on the server..., and
not even in any of the other folders on the server.
- Icedove#1 thinks incoming e-mail is spam, and moves it to the spam-folder
- server uses that folder to train spamassassin and marks them for deletion
- Icedove#2 expunges all messages marked for deletion because `oh look how much space I could save!'