code: protected function initOptions()
      {
          if($this->grid){
              $this->options = array_merge([
              'class' => $this->getGridClass().isset($this->options['class']) ? ' '.$this->options['class'] : '',
              ], $this->options);
          }else{
              $this->options = array_merge([
              'class' => self::DEFAULT_TYPE.self::SIZE_DEFAULT,
              ], $this->options);
          }
      }
docs: Initializes the widget options.
  This method sets the default values for various options.