Index: wp-includes/widgets.php
===================================================================
--- wp-includes/widgets.php	(revision 6321)
+++ wp-includes/widgets.php	(working copy)
@@ -86,8 +86,6 @@
 
 	global $wp_registered_widgets, $wp_register_widget_defaults;
 
-	$id = sanitize_title($id);
-
 	if ( empty($output_callback) ) {
 		unset($wp_registered_widgets[$id]);
 		return;
@@ -142,8 +140,6 @@
 function wp_register_widget_control($id, $name, $control_callback, $options = array()) {
 	global $wp_registered_widget_controls, $wp_register_widget_defaults;
 
-	$id = sanitize_title($id);
-
 	if ( empty($control_callback) ) {
 		unset($wp_registered_widget_controls[$id]);
 		return;