Missing something?

Hi everyone,

Just trying to use this addon, but actually isn't working on my SilverStripe 3 project. Here the case:

mysite/code/DuplicaEvento.php

<?php

  /**
  * Classe Duplica
  */
  class DuplicaEvento extends ModelAdmin {
	// Dichiarazione Proprietà
	private static $managed_models = array(
        'EventoCorrelato' // <- This is my DataObject related to the destination Grid
	);

    /**
    * Override funzione Form
    **/
    function getEditForm($id = null, $fields = null) {
	  $form = parent::getEditForm($id, $fields);
	  $nomeGriglia = 'EventiCorrelati'; // Trying to filter a specified Grid
	  $griglia = $form->Fields()->fieldByName($nomeGriglia);

	  if ($griglia) {
		$griglia->getConfig()->addComponent(new GridFieldCopyButton());
	  }

	  return $form;
    }
  }

I tried the main example too, with no results. My doubt is related to the fact that EventiCorrelati is a grid extended and implemented in pair with another extension (to be more specific I'm using sortablegridfield). In the first place I thought that can should be the cause. But, by trying with typical situation as standard GridFields - without any addon - the button still not appear.

Any ideas?

Thanks in advance.