commit 5b4c17d6292956f7476057cb978877915e313927
Author: Jay Callicott <jrcallicott@gmail.com>
Date:   Sat Jun 8 20:31:13 2013 -0500

    #58

diff --git a/core/modules/filter/filter.module b/core/modules/filter/filter.module
index 5c52604..b716149 100644
--- a/core/modules/filter/filter.module
+++ b/core/modules/filter/filter.module
@@ -1000,16 +1000,9 @@ function filter_dom_serialize_escape_cdata_element($dom_document, $dom_element,
  */
 function template_preprocess_filter_guidelines(&$variables) {
   $format = $variables['format'];
-  // Remove default 'filter-guidelines' class from attributes, but leave other
-  // classes.
-  // @todo: Remove this hack once http://drupal.org/node/1938430 lands.
-  $key = array_search('filter-guidelines', $variables['attributes']['class']->value());
-  if ($key !== FALSE) {
-    unset($variables['attributes']['class'][$key]);
-  }
+
   $variables['attributes']['class'][] = 'filter-guidelines-item';
   $variables['attributes']['class'][] = 'filter-guidelines-' . $format->format;
-  $variables['attributes'] = new Attribute($variables['attributes']);
 
   $variables['tips'] = array(
     '#theme' => 'filter_tips',