/**
* Returns the button that was used to submit the form.
*
* @return Button|null The clicked button or NULL if the form was not
* submitted
*/
public function getClickedButton()
{
if ($this->clickedButton) {
return $this->clickedButton;
}
if ($this->parent && method_exists($this->parent, 'getClickedButton')) {
return $this->parent->getClickedButton();
}
}