Index: wp-admin/js/link.js
===================================================================
--- wp-admin/js/link.js	(revision 6765)
+++ wp-admin/js/link.js	(working copy)
@@ -34,6 +34,7 @@
 	};
 	jQuery('#categorychecklist').wpList( {
 		alt: '',
+		what: 'link-category',
 		response: 'category-ajax-response',
 		addAfter: catAddAfter
 	} );