Hi,

I have been experimenting with this module to allow anonymous users to easily login/register via Facebook during checkout:
https://www.drupal.org/project/simple_fb_connect

As the module suggested in readme.txt, i have implemented a ?destination=.current_path() redirect after succesfull login with this hook_form_alter:

function custom_couture_checkout_form_alter(&$form, &$form_state, $form_id) {
if ($form['#form_id']=='commerce_checkout_form_checkout') {
  global $user;
  if (!$user->uid && !empty($form['account'])) { 
$form['account']['login']['fb_login'] = array(
        '#type' => 'item',
      '#title' => t('Or quickly connect with facebook to create your account or login'),
        '#markup' => '<a href="/user/simple-fb-connect?destination=' . current_path() . '"><img src="/sites/default/files/Facebook-login.png"></a>',
      );
$form['account']['login']['mail_confirm']['#description'] = t('Provide your e-mail address in the above fields to activate your account during this checkout.');      
  }
} 
}

Now, what happens after facebook login redirect ?

The checkout cart contents summary, which has a collapsible fieldset, becomes for some reason cleared. Also on the checkout review pane near the end.
I believe this could have something to do with Orenmode customization inside /sites/all/themes/md_orenmode/template.php.

You can witness the behaviour on http://couture.artstanding.be.
I have sent login credentials to [email protected]

Thanks upfront for having a look at this issue!