Drupal多表单在页面刷新时失去状态

我有一个多页表单。浏览第一页，第二页，然后第三页。按刷新键(f5)，表单返回到第2页。

这是drupal-6。问题看起来类似于这个http://drupal.org/node/1060290。

通过form_cache数据库表深入研究这个问题。第1页和第2页的数据都出现在那里。在php调试器中，看起来好像已经创建了一个新的form_id。ie。storage_form- 1add3819chea88139679819935a69686是数据库缓存表中的键，form-bcf9556f57f5352a57dfbba4c2120ee7是刷新时的'form_id'。

我的表单代码看起来像什么?

主要表单功能:

function myform_online(&$form_state) {
  // $form_state['storage']['step'] keeps track of what page we're on.
  // start at step 1 if no storage has been set
  if (!isset($form_state['storage']['step'])) {
    $form_state['storage']['step'] = 1;
 }
 // If we are saving the form data we should submit rather than display the details.
 // At least look at saving the step.
 // Don't lose our old data when returning to a page with data already typed in.
 $default_values = array();
 if (isset($form_state['storage']['values'][$form_state['storage']['step']])) {
    $default_values = $form_state['storage']['values'][$form_state['storage']['step']];
 }
 switch ($form_state['storage']['step']) {
    case 1:
        // Your Details
        module_load_include('inc', 'join_online', 'includes/step1'); 

我们处理submit:

function join_online_submit($form, &$form_state) {
//Save the values for the current step into the storage array.
//dsm($form_state); 
$form_state['storage']['values'][$form_state['storage']['step']] = $form_state['values'];
# ahah - bail.
if ($form_state['ahah_submission']) {
    return;
}
// How do we work out if this was a refresh? It currently does start with 1 and think that the step is #2. 
//Check the button that was clicked and change the step.
if ($form_state['clicked_button']['#id'] == 'edit-previous') {
    $form_state['storage']['step']--;
} elseif ($form_state['clicked_button']['#id'] == 'edit-next') {
    $form_state['storage']['step']++;
} elseif ($form_state['clicked_button']['#id'] == 'edit-finish') {
    //You should store the values from the form in the database here.
    //We must do this or the form will rebuild instead of refreshing.
    unset($form_state['storage']);
    //Go to this page after completing the form.
    $form_state['redirect'] = 'join_online/form/thank-you';
}
}