Write a "notmuch show" that displays a single thread. Fix to use the *last* Message-ID header if multiple such headers are encountered, (I noticed this is one thing that kept me from seeing the same message-ID values as sup). Fix "notmuch restore" to delete the old tags from a message/thread before adding new ones. This will require someway to temporarily 'disconnect' a notmuch_message_t from the database, (that it, disable automatic sync for add_tag, etc.), and then reconnect it. That is, the removal and subsequent addition of tags to the message/thread needs to be transactional.