'This is a multilingual variable.' doesn't show up in nested form elements.

I came across this problem in the Organic Groups module on the configuration page for 'Messaging & Notifications'. The page there is basically a big Drupal form containing various settings. In the code ik looks like this: (I deleted most of the form here and only copied the interesting part)

Array
(
    [og_settings] => Array
        (
             ...
             [notifications] => Array
                (
                    [#type] => fieldset
                    [#title] => Messaging & Notifications
                    [#collapsible] => 1
                    [#collapsed] => 1
                    [og_email_notification_pattern] => Array
                        (
                            [#type] => textfield
                            [#title] => Format of "From:" field
                            [#default_value] => @user_name  <@site_mail>
                            [#description] => Specify the format of the "From:" field on outgoing notifications. Available variables: @user_mail, @user_name, @site_mail, @site_name. Note that the @user_mail token reveals the author's email address. If the admin email examples above appear blank, you need to set your site email in the "Site information" panel.
                        )

                    [og_new_node_subject] => Array
                        (
                            [#type] => textfield
                            [#title] => Nieuw onderwerp
                            [#description] => Subject of notification message for new content. Available variables: @group, !group_url, @type, @site, !content_url, !reply_url, @title, @subject, @node_full, @node_teaser, @username. %subject contains the comment title in the case of a comment but the node title in the case of a new post. @title is always the node title.
                            [#default_value] => @group: '@title' op @site
                        )
                     ...
               )
            ...
        )
)

This array is then processed by the i18n_form_alter_settings(&$form, &$variables) function that - as far as I can tell - just adds the text This is a multilingual variable. to variables that are configured to be multilingual in the $conf['i18n_variables'] array in settings.php.

The entries 'og_email_notification_pattern', 'og_new_node_subject', ... don't get processed by the i18n_form_alter_settings function so the text This is a multilingual variable. is not added.

I have corrected this problem by changing the function from:

/**
 * Check for multilingual variables in form.
 */
function i18n_form_alter_settings(&$form, &$variables) {
  $result = 0;
  foreach (element_children($form) as $field) {
    if (isset($form[$field]['#type']) && $form[$field]['#type'] == 'fieldset') {
      $result += i18n_form_alter_settings($form[$field], $variables);
    }
    elseif (in_array($field, $variables)) {
      $form[$field]['#description'] .= ' <strong>'. t('This is a multilingual variable.') .'</strong>';
      $result++;
    }
  }
  return $result;
}

to:

/**
 * Check for multilingual variables in form.
 */
function i18n_form_alter_settings(&$form, &$variables) {
  $result = 0;
  foreach (element_children($form) as $field) {
    $possible_deeper_children = element_children($form[$field]);
    if (is_array($possible_deeper_children) && !empty($possible_deeper_children)) {
        foreach ($possible_deeper_children as $child) {
            $result += i18n_form_alter_settings($form[$field][$child], $variables);
        }
    }
    if (isset($form[$field]['#type']) && $form[$field]['#type'] == 'fieldset') {
      $result += i18n_form_alter_settings($form[$field], $variables);
    }
    elseif (in_array($field, $variables)) {
      $form[$field]['#description'] .= ' <strong>'. t('This is a multilingual variable.') .'</strong>';
      $result++;
    }
  }
  return $result;
}

This code seems to work very nice but it would be great if someone with more experience on the i18n project could verify the changes.