public function GetChangableFieldNames()
    {
        $aFieldNames = $this->GetFromInternalCache('aChangableFieldNames');
        if (is_null($aFieldNames)) {
            $aFieldNames = array();
            $oFields = $this->GetFieldCmsFieldConfList();
            while ($oField = $oFields->Next()) {
                $aFieldNames[] = $oField->fieldName;
            }
            $oFields->GoToStart();
            $this->SetInternalCache('aChangableFieldNames', $aFieldNames);
        }

        return $aFieldNames;
    }