initDefaultButtons() protected method

Merges buttons with default configurations.
protected initDefaultButtons ( )
 /** @inheritdoc */
 protected function initDefaultButtons()
 {
     parent::initDefaultButtons();
     $this->buttons['edit'] = $this->buttons['update'];
     unset($this->buttons['update']);
     $this->buttons['view']['options'] = ['target' => '_blank'];
     array_walk($this->buttons, function (&$item) {
         $item['options'] = ArrayHelper::merge($item['options'], ['class' => 'btn btn-default btn-sm']);
     });
 }