* Due to the outdated rights we can flag the message as deleted (we still have append), but we cannot expunge the message.
* On the next sync an inconsitency is detected, the whole folder is resynced, and we end up with a message that is marked as deleted in the message list.
Either the Append rights needs to be in a way that we don't mark as deleted if we can't expunge as well, or we should filter flagged as deleted messages (which breaks all of the message count assumtions), or we somehow hide the deleted message, or we enable the user to restore the message.
In any case, the message should either vanish from the users view if he can delete it, or he needs to be told why he can't delete the message (no expunge rights)