[flexcoders] Strange behavior

[markgoldin_2000]

I am trying to implement a checkbox as a headerRenderer:
public class CheckBoxHeaderRenderer extends CheckBox
{
        private var _parentGrid:DataGrid = new DataGrid();
        public function CheckBoxHeaderRenderer()
        {
                super();
                selected = true;
                addEventListener("click", clickHandler);
        }       
        override protected function clickHandler
(event:MouseEvent):void
        {
                super.clickHandler(event);
                parentGrid.dataProvider[0].processorder = 10;
        }
        public function set parentGrid(value:DataGrid):void
        {
                _parentGrid = value;
        }
        public function get parentGrid():DataGrid
        {
                return _parentGrid;
        }
  }
That works fine except that when I click on a checkbox it does not 
lose it "check" mark. Commenting out:
parentGrid.dataProvider[0].processorder = 10;
will resore checkbox's behavior. What am I missing?

Thanks