 		private function columnListRollOverHandler(event:Event):void
 		{
 			var list:List = event.target as List;
+			if (list == null) return;
 			for(var i:int=0; i < columns.length; i++) {
 				if (list != columns[i]) {
 					var otherList:List = columns[i] as List;

			var value:Object = ValuesManager.valuesImpl.getValue(_strand, "background-color");
			if (value != null) backgroundColor = Number(value);
			
			//background.graphics.clear();
			//background.graphics.beginFill(backgroundColor);
			//background.graphics.drawRect(0,0,sw,sh);
			//background.graphics.endFill();
			
			buttonBar.x = 0;
			buttonBar.y = 0;
			buttonBar.width = sw;
			buttonBar.height = 25;
			
			columnContainer.x = 0;
			columnContainer.y = 30;
			columnContainer.width = sw;
			columnContainer.height = sh - 25;
			
			var colXpos:Number = 0;
			
			for(var i:int=0; i < columns.length; i++) {
				var column:List = columns[i];
			
				var cw:Number = sw/(columns.length);
				column.y = 0;
				column.x = colXpos;
				column.height = columnContainer.height; // this will actually be Nitem*rowHeight
				
				colXpos += column.width;
			}
			
			IEventDispatcher(_strand).dispatchEvent(new Event("layoutComplete"));

			
			var sharedModel:IDataGridModel = _strand.getBeadByType(IBeadModel) as IDataGridModel;
			
			// create an array of columnLabels for use by the ButtonBar/DataGrid header.
			var columnLabels:Array = new Array();
			var buttonWidths:Array = new Array();
