* commit '05f92b7c5810dfc4e96cd5dddff1f7f380739136': Update roots when data cleared, refresh UI. Treat document thumbnails as preemptable.
* commit '05f92b7c5810dfc4e96cd5dddff1f7f380739136': Update roots when data cleared, refresh UI. Treat document thumbnails as preemptable.