protected function handleCheckBoxFields()
 {
     $newGP = Tx_Formhandler_StaticFuncs::getMergedGP();
     //check for checkbox fields using the values in $newGP
     if ($this->settings['checkBoxFields']) {
         $fields = t3lib_div::trimExplode(',', $this->settings['checkBoxFields']);
         foreach ($fields as $idx => $field) {
             if (!isset($newGP[$field]) && isset($this->gp[$field])) {
                 if ($this->lastStep < $this->currentStep) {
                     $this->gp[$field] = array();
                 }
             }
         }
     }
 }