Hey list, I've got a couple forms that use AHAH functions to generate a drop down of states/provinces based on the user's selection in a country drop down menu. I'm using a very similar method as is found here: http://drupal.org/node/331941 One form works fine with fields as $form['country'] and $form['state']. The other form uses fieldsets and those fields get renamed and lose their hierarchy after the form is rebuilt. So for example, the following fields start out like: $form['guest'][1]['country'] $form['guest'][1]['state'] $form['guest'][1]['zip'] But after the form is rebuilt with form_builder and drupal_render using: $output = drupal_render($form['guest'][1]['state']); $output .= drupal_render($form['guest'][1]['zipcode']); // Render form output as JSON print drupal_json(array('data' => $output, 'status' => true)); The rebuilt fields are logically placed outside of the fieldset and end up as: $form_state['guest'][1]['country'] $form_state['state'] $form_state['zip'] Thoughts on what might cause that? Thanks for any direction. I've struggled with this for hours! Jeff