GrapeCity.Win.Spread.InputMan.CellType.GcDateTimeCellType datecell = new GrapeCity.Win.Spread.InputMan.CellType.GcDateTimeCellType();
fpSpread1.Sheets[0].Cells[0, 0].CellType = datecell;
datecell.DropDownCalendar.BackColor = Color.Red;
datecell.DropDownCalendar.CalendarDimensions = new Size(3, 1);
datecell.DropDownCalendar.Font = new Font("Arial", 10, FontStyle.Bold);
datecell.DropDown.AllowDrop = true;
datecell.DropDown.AllowResize = true;
datecell.DropDown.AutoDropDown = true;
datecell.DefaultActiveField = datecell.Fields[2];