Hi there ive found another minor issue:
this command in the controller
$this->grocery_crud->change_field_type('IDAGENTEREF','hidden');
dont work anymore ( in the sense that the field remains visibile in read, edit and add )
IF and only IF IDAGENTEREF derives from a relation e.g.
$this->grocery_crud->set_relation('IDAGENTEREF','AGENTI','AC_COGNOME');
Thank you for your attention