Force Redraw a Flex Tree component, try to keep opened items opened and keep selection

gistfile1.as

		private function _forceRedraw(tree:Tree):void
		{
			var scrollPosition:Number = tree.verticalScrollPosition;
			var openItems:Object = tree.openItems;
			var dataProvider:*=tree.dataProvider;
			var index:int=tree.selectedIndex;
			var item:*=tree.selectedItem;
			tree.dataProvider = null;
			tree.dataProvider = dataProvider;
			tree.openItems = openItems;
			
			tree.validateNow();
			tree.verticalScrollPosition = scrollPosition;
			tree.selectedIndex=index;
			tree.selectedItem=item;
		}