Index: wp-admin/js/common.dev.js
===================================================================
--- wp-admin/js/common.dev.js	(revision 21089)
+++ wp-admin/js/common.dev.js	(working copy)
@@ -216,7 +216,7 @@
 			m.addClass('sub-open');
 		},
 		out: function(){
-			$(this).find('.wp-submenu').removeClass('sub-open');
+			$(this).find('.wp-submenu').removeClass('sub-open').css('margin-top', '');
 		},
 		timeout: 200,
 		sensitivity: 7,