View difference between Paste ID: yiJNGrSC and 07WfQTkw

 <?php
 
 function test_menu() {
   $items = array();
   $items['test'] = array(
     'title' => 'Test',
     'page callback' => 'test_page_handler',
     'access callback' => TRUE,
   );
   return $items;
 }
 
 function test_page_handler() {
-  $output = drupal_get_form('test_simple_form');
+  $output = drupal_get_form('test_simple_form', $data);
   return $output;
 }
 
 function test_simple_form(&$form_state) {
   // If the form has already been built, and we already have the data, don't load it again.
   if (isset($form_state['values']['expensive_data'])) {
     $data = $form_state['values']['expensive_data'];
   }
   else {
     // Otherwise get the data from source.
     $data = very_expensive_data_operation();
   }
   // Store the data
   $form['expensive_data'] = array(
     '#type' => 'value',
     '#value' => $data
   );
 
   $form['create'] = array(
     '#type' => 'submit',
     '#value' => t('Submit'),
   );
   return $form;
 }
 
 function test_simple_form_submit(&$form, &$form_state) {
-  // do something
+  $form_state['rebuild'] = TRUE;
   drupal_set_message('Submit');
 }
 
 function very_expensive_data_operation() {
   drupal_set_message('Running VEDO ' . time());
   sleep(1);
   return array(1,2,3,4,5,6,7,8,9);
 }