Do not use pid for sotring

Classes/Controller/BackendController.php

@@ -137,10 +137,11 @@ class BackendController extends ActionController {
 						$sortingData['next'][$prevUid] = '-' . $job->getUid();
 						$sortingData['prevUid'][$job->getUid()] = $prevUid;
 					}
-					$prevPrevUid = isset($sortingData['prev'][$job->getUid()]) ? -$prevUid : $job->getPid();
+					$prevPrevUid = isset($sortingData['prev'][$job->getUid()]) ? -$prevUid : 0;
 					$prevUid = $job->getUid();
 				}
 			}
+
 			$this->view->assign('sortingData', $sortingData);
 
 			// get all Locations