/**
  * Mark a tacker as deleted
  * @see www/tracker/admin/index.php L908:919
  *
  * @param $artifactType Tracker to be deleted
  *
  * @return Boolean
  */
 function preDeleteArtifactType(ArtifactType $artifactType)
 {
     if ($artifactType->preDelete(true)) {
         $arm = new ArtifactRulesManager();
         $arm->deleteRulesByArtifactType($artifactType->getID());
         $referenceManager = ReferenceManager::instance();
         $ref = $referenceManager->loadReferenceFromKeywordAndNumArgs(strtolower($artifactType->getItemName()), $this->getGroup()->getGroupId(), 1);
         if ($ref) {
             $referenceManager->deleteReference($ref);
         }
         return true;
     }
     return false;
 }