Index: wp-admin/js/widgets.js
===================================================================
--- wp-admin/js/widgets.js (revision 20017)
+++ wp-admin/js/widgets.js (working copy)
@@ -240,8 +240,10 @@
     if(c=c.val()){
         c=c.replace(/<[^<>]+>/g,"").replace(/</g,"&lt;").replace(/>/g,"&gt;");
         a(b).children(".widget-top").children(".widget-title").children().children(".in-widget-title").html(": "+c)
-    }
-},
+        } else {
+        a(b).children(".widget-top").children(".widget-title").children().children(".in-widget-title").empty()
+        }
+    },