Drupal form #states using OR
it is no right at all, this is the right way to make an OR:

$form['problem'] = array(
  '#type' =&gt; 'textarea',
  '#title' =&gt; t('Problem'),
  '#states' =&gt; array(
    'visible' =&gt; array(
      array(
        ':input[name="product_type"]'=&gt; array(
          array('value' =&gt; 'b'),
          array('value' =&gt; 'c'),
        ),
      ),
    ),
  ),
);


Regards