partial void btn_expand(UIButton sender)
        {
            stkSummary.Hidden  = !stkSummary.Hidden;

            if (stkSummary.Hidden) {

                btnExpand.SetImage(UIImage.FromBundle("Dashboard_Plus_Button"), UIControlState.Normal);
            }
            else if (!stkSummary.Hidden){
                btnExpand.SetImage(UIImage.FromBundle("Dashboard_Minus_Button"), UIControlState.Normal);
            }
        }