diff --git a/ctools_ajax_sample/ctools_ajax_sample.module b/ctools_ajax_sample/ctools_ajax_sample.module
index 4638ac3..2779dc6 100644
--- a/ctools_ajax_sample/ctools_ajax_sample.module
+++ b/ctools_ajax_sample/ctools_ajax_sample.module
@@ -558,7 +558,7 @@ function ctools_ajax_sample_start($form, &$form_state) {
     '#title' => t('Choose your animal'),
     '#type' => 'radios',
     '#options' => $options,
-    '#default_value' => $form_state['object']->type,
+    '#default_value' => $form_state['object']->type !== 'unknown' ? $form_state['object']->type : NULL,
     '#required' => TRUE,
   );
 
@@ -595,7 +595,7 @@ function ctools_ajax_sample_configure_sheep($form, &$form_state) {
       t('Merino') => t('Merino'),
       t('Corriedale') => t('Coriedale'),
     ),
-    '#default_value' => !empty($form_state['object']->sheep) ? $form_state['object']->sheep : '',
+    '#default_value' => !empty($form_state['object']->sheep) ? $form_state['object']->sheep : NULL,
     '#required' => TRUE,
   );
   return $form;
@@ -680,7 +680,7 @@ function ctools_ajax_sample_configure_raptor($form, &$form_state) {
       t('Owl') => t('Owl'),
       t('Buzzard') => t('Buzzard'),
     ),
-    '#default_value' => !empty($form_state['object']->raptor) ? $form_state['object']->raptor : '',
+    '#default_value' => !empty($form_state['object']->raptor) ? $form_state['object']->raptor : NULL,
     '#required' => TRUE,
   );