Index: modules/system/system.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.module,v
retrieving revision 1.845
diff -u -p -r1.845 system.module
--- modules/system/system.module	28 Nov 2009 09:36:41 -0000	1.845
+++ modules/system/system.module	28 Nov 2009 19:29:09 -0000
@@ -3042,13 +3042,16 @@ function system_page_build(&$page) {
       '#markup' => theme('system_run_cron_image', array('image_path' => 'system/run-cron-image')),
     );
   }
+}
 
-  // Find all block regions so they can be rendered.
+/**
+ * Implements hook_page_alter().
+ */
+function system_page_alter(&$page) {
+  // Find all non-empty page regions, and add a theme wrapper function that
+  // allows them to be consistently themed.
   $regions = system_region_list($GLOBALS['theme']);
-
-  // Load all region content assigned via blocks.
   foreach (array_keys($regions) as $region) {
-    // Don't render empty regions.
     if (!empty($page[$region])) {
       $page[$region]['#theme_wrappers'][] = 'region';
       $page[$region]['#region'] = $region;