ctools_wizard_multistep_form isn't adding buttons to forms

I'm making multistep modal form by following the example in ctools_ajax_sample.module.
I'm not seeing any Next/Cancel buttons added to my form, nor do I see the trail; None of the form components added in the ctools_wizard_wrapper() wrapper_callback are added to my form, despite the $form_info I'm passing to ctools_wizard_multistep_form() being (apparently) correct. Dumping $form immediately after calling ctools_wizard_multistep_form($form_info, $step, $form_state) in my code shows no buttons or ctools_trail, but it does in the example code.

Here's my definition of $form_info:

  $form_info = array(
    'id' => 'create_ticket',
    'path' => "support/" . ($js ? 'ajax' : 'nojs') . "/modal/%step",
    'show trail' => TRUE,
    'show back' => TRUE,
    'show cancel' => TRUE,
    'show return' => FALSE,
    'next callback' => 'create_ticket_next',
    'finish callback' => 'create_ticket_finish',
    'cancel callback' => 'create_ticket_cancel',
    
    'order' => array(
      'select_site' => t('Select a site'),
      'ticket' => t('Create a ticket'),
    ),
    'forms' => array (
      'select_site' => array(
        'form id' => 'select_site_form',
      ),
      'ticket' => array(
        'form id' => 'parature_ticket_form',
      ),
    ),
  );

And here's where I call ctools_wizard_multistep_form, which doesn't include the multistep form buttons and trail (unlike in the example). Instead, the result is just the plain form as defined in the function that defines it.

  $form = ctools_wizard_multistep_form($form_info, $step, $form_state);
  $output = drupal_render($form);

I have confirmed that the wrapper_callback, ctools_wizard_wrapper (which is supposed to add these elements to the form), is being called. But nothing is added to the form.