Index: wp-admin/js/postbox.dev.js
===================================================================
--- wp-admin/js/postbox.dev.js	(revision 17550)
+++ wp-admin/js/postbox.dev.js	(working copy)
@@ -82,7 +82,9 @@
 		init : function(page, args) {
 			$.extend( this, args || {} );
 			$('#wpbody-content').css('overflow','hidden');
-			$('.meta-box-sortables').sortable({
+			// Bug #16643
+			var selector = ( $.browser.msie && parseInt( $.browser.version ) <= 8 ) ? '.meta-box-sortables:not(#side-sortables)' : '.meta-box-sortables';
+			$(selector).sortable({
 				placeholder: 'sortable-placeholder',
 				connectWith: '.meta-box-sortables',
 				items: '.postbox',