protected function getDisplayText(Node $node) {
    if ($this->isRootTypeNode($node->getOID())) {
      $mapper = $node->getMapper();
      return $mapper->getTypeDisplayName($this->getMessage());
    }
    else {
      return strip_tags(preg_replace("/[\r\n']/", " ", NodeUtil::getDisplayValue($node)));
    }
  }