New form element aren't processed properly in ctools_process_form()

I think the following is a bug, but it might turn out as a support request.

Consider the following code that depends on date_popup module (from the Date package). It seems that the date_popup that is added in the submit handler isn't processed resulting with a non-working field -- while the form added in the original form is working properly.

/**
 * Form builder.
 */
function foo_form(&$form_state) {
  $form = array();

  $form['select'] = array(
    '#type' => 'select',
    '#title' => t('Select'),
    '#options' => array(1, 2, 3),
    '#attributes' => array('class' => 'ctools-auto-submit'),
  );

  $form['static_date'] = array(
    '#type' => 'date_popup', // This element is processed properly. 
    '#title' => t('Start date static'),
    '#default_value' => '',
    '#date_format' => 'm/d/Y',
    '#weight' => 5,
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Apply'),
    '#attributes' => array('class' => 'ctools-use-ajax ctools-auto-submit-click'),
    '#weight' => 99,
  );

  ctools_add_js('ajax-responder');
  ctools_add_js('auto-submit');
  drupal_add_js('misc/jquery.form.js');

  $form['#prefix'] = '<div class="clear-block" id="example-form">';
  $form['#suffix'] = '</div>';

  return $form;
}

/**
 * Submit handler.
 */
function foo_form_submit(&$form, &$form_state) {

  $form['date'] = array(
    '#type' => 'date_popup', // This date popup isn't procesed.
    '#title' => t('Start date'),
    '#default_value' => '',
    '#date_format' => 'm/d/Y',
    '#weight' => 5,
  );
}