/**
  * delete linked objects (notes, relations, ...) of record
  *
  * @param Tinebase_Record_Interface $_record
  */
 protected function _deleteLinkedObjects(Tinebase_Record_Interface $_record)
 {
     // use textfilter for contract_id
     $filter = new Sales_Model_ProductAggregateFilter(array());
     $filter->addFilter(new Tinebase_Model_Filter_Text(array('field' => 'contract_id', 'operator' => 'equals', 'value' => $_record->getId())));
     Sales_Controller_ProductAggregate::getInstance()->deleteByFilter($filter);
     parent::_deleteLinkedObjects($_record);
 }