次のサンプルコードは、列ヘッダ内の最初のセルの背景色を赤に変更します。
FarPoint.Web.Spread.ColumnHeader colhdr;
colhdr = FpSpread1.ActiveSheetView.ColumnHeader;
colhdr.Cells[0, 0].BackColor = Color.Red;
Dim colhdr As FarPoint.Web.Spread.ColumnHeader
colhdr = FpSpread1.ActiveSheetView.ColumnHeader
colhdr.Cells.Item(0, 0).BackColor = Color.Red