Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.564
diff -u -r1.564 theme.inc
--- includes/theme.inc	7 Jan 2010 14:48:56 -0000	1.564
+++ includes/theme.inc	7 Jan 2010 23:50:35 -0000
@@ -812,6 +812,8 @@
     foreach ($info['includes'] as $include_file) {
       include_once DRUPAL_ROOT . '/' . $include_file;
     }
+    // No need to repeat this when theme function is called multiple times.
+    unset($hooks[$hook]['includes']);
   }
 
   // If a renderable array is passed as $variables, then set $variables to