public function addFieldToGridCollection($alias, $params, $block, $collection)
 {
     // Add main field in all cases
     parent::addFieldToGridCollection($alias, $params, $block, $collection);
     // Add use_config field if needed
     if ($this->getIsUseConfigField()) {
         $this->_useConfigMode = true;
         parent::addFieldToGridCollection($alias . '_cpi_uc', $params, $block, $collection);
         $this->_useConfigMode = false;
     }
 }