protected function processValues()
    {
        $form = $this->getForm();
        $data = &$form->getFormData();

        if (isset($data[$this->id])) {
            if (is_array($data[$this->id])) {
                $this->values = $data[$this->id];
            } elseif ($data[$this->id] != '') {
                $this->values = array($data[$this->id]);
            } else {
                $this->values = array();
            }
        } else {
            $this->values = array();
        }
    }