modify JFormFieldForeignKey

Hi, I modified the file foreignkey.php, adding the ability to sort the field.
First add to JFormFieldForeignKey  class and getInput function this:
$this->order_field = $this->getAttribute('order_field');
 and modified the query:
$query
                ->select(
                        array(
                            $this->key_field,
                            $this->value_field
                        )
                )
                ->from($this->table)
                ->order($this->order_field);

and in form xml filed generated add:
order_field="activity"

Maybe you can modify the component creator to add this feature

best regards
Francesco Reitano