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* Fix for all sorts of incompatibilities with other extensions; Mozilla bug 174320 is responsible for that (though that bug wouldn't have surfaced if I had done things slightly different).
* Added troubleshooting option for some IMAP servers which only download the first message body when moving or copying several messages. Kudos to Ketil Lund who reported this problem and greatly helped me in ironing out the kinks of this new release.
* Added a nifty new "Report a Bug" wizard (available from the "Options" dialog) to encourage users to write bug reports when something's not working, and to help them doing it in a way that's useful to me.
Also, there's an all-new options dialog explaining which Thunderbird settings affect Sync On Arrival (to, among other things, make clearer that the "Select folder for offline use" option controls whether Sync On Arrival downloads message bodies).