Ticket #4410: speed.patch

Index: ui/ui.sortable.js
===================================================================
--- ui/ui.sortable.js	(revision 2391)
+++ ui/ui.sortable.js	(working copy)
@@ -52,9 +52,6 @@
 
 		if(this.options.disabled || this.options.type == 'static') return false;
 
-		//We have to refresh the items data once first
-		this._refreshItems(event);
-
 		//Find out if the clicked node (or one of its parents) is a actual item in this.items
 		var currentItem = null, self = this, nodes = $(event.target).parents().each(function() {
 			if($.data(this, 'sortable-item') == self) {
@@ -83,7 +80,8 @@
 		var o = this.options, self = this;
 		this.currentContainer = this;
 
-		//We only need to call refreshPositions, because the refreshItems call has been moved to mouseCapture
+		// moving the refreshItems call to mouseCapture slows things down big time with large lists
+		this._refreshItems(event);
 		this.refreshPositions();
 
 		//Create and append the visible helper