protected function addQueryBuilderSearchResults(DataList $documents)
    {
        /** @var ManyManyList $originals Documents that belong to just this set. */
        $originals = $this->Documents();
        $originals->removeByFilter('"ManuallyAdded" = 0');

        foreach ($documents as $document) {
            $originals->add($document, array('ManuallyAdded' => 0));
        }

        return $originals;
    }