public function delFELayer()
 {
     $criteria = $this->getCriteria();
     $criteria->select('layers.idLayer');
     $criteria->where("idAnnotationSet = {$this->getId()}");
     $criteria->where("layers.layertype.entry = 'lty_fe'");
     $query = $criteria->asQuery();
     $rows = $query->getResult();
     $maxIdLayer = 0;
     foreach ($rows as $row) {
         if ($row['idLayer'] > $maxIdLayer) {
             $maxIdLayer = $row['idLayer'];
         }
     }
     if ($maxIdLayer > 0) {
         $layer = new Layer($maxIdLayer);
         $layer->delete();
     }
 }