FarPoint.Web.Spread.Model.GroupDataModel gm = new FarPoint.Web.Spread.Model.GroupDataModel(FpSpread1.ActiveSheetView.DataModel);
FarPoint.Web.Spread.SortInfo[] sort = new FarPoint.Web.Spread.SortInfo[1];
sort[0] = new FarPoint.Web.Spread.SortInfo(0, true);
gm.Group(sort, System.Collections.Comparer.Default);
FpSpread1.ActiveSheetView.DataModel = gm;
FarPoint.Web.Spread.Model.Group dg = new FarPoint.Web.Spread.Model.Group(gm, (FarPoint.Web.Spread.Model.Group)gm.Groups[0], 0, true);
TextBox1.Text = FpSpread1.ActiveSheetView.GetGroupInfo(dg).BackColor.ToString();