Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.272
diff -u -p -r1.272 form.inc
--- includes/form.inc	6 May 2008 12:18:45 -0000	1.272
+++ includes/form.inc	6 Jun 2008 01:09:12 -0000
@@ -2033,7 +2033,7 @@ function theme_textfield($element) {
 function theme_form($element) {
   // Anonymous div to satisfy XHTML compliance.
   $action = $element['#action'] ? 'action="' . check_url($element['#action']) . '" ' : '';
-  return '<form ' . $action . ' accept-charset="UTF-8" method="' . $element['#method'] . '" id="' . $element['#id'] . '"' . drupal_attributes($element['#attributes']) . ">\n<div>" . $element['#children'] . "\n</div></form>\n";
+  return '<form ' . $action . ' accept-charset="UTF-8" method="' . $element['#method'] . '" id="' . form_clean_id($element['#id']) . '"' . drupal_attributes($element['#attributes']) . ">\n<div>" . $element['#children'] . "\n</div></form>\n";
 }
 
 /**