Index: modules/filter/filter.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/filter/filter.module,v
retrieving revision 1.239
diff -u -p -r1.239 filter.module
--- modules/filter/filter.module	30 Dec 2008 16:43:17 -0000	1.239
+++ modules/filter/filter.module	5 Jan 2009 18:12:02 -0000
@@ -1142,7 +1142,7 @@ function _filter_xss_attributes($attr) {
   }
 
   // the attribute list ends with a valueless attribute like "selected"
-  if ($mode == 1) {
+  if ($mode == 1 && !$skip) {
     $attrarr[] = $attrname;
   }
   return $attrarr;