/**
  * @internal Will create a new sample based on changed settings.
  * 
  * @attribute[RequestParam('append_timezone','bool')]
  * @attribute[RequestParam('timezone','string')]
  * @attribute[RequestParam('dtf','string')]
  * @attribute[RequestParam('culture_code','string')]
  */
 public function RefreshSample($append_timezone, $timezone, $dtf, $culture_code)
 {
     $this->culture_code = $culture_code;
     $this->timezone = $timezone;
     $txt = $this->_sample($dtf);
     if ($append_timezone) {
         $txt .= " {$timezone}";
     }
     $sample = new Control('span');
     $sample->append("({$txt})")->css('color', 'gray');
     return AjaxResponse::Renderable($sample);
 }