private void RadGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
    GridSelectCellElement selectCell = e.CellElement as GridSelectCellElement;
    if (selectCell != null && e.RowIndex > 2)
    {
        selectCell.Enabled = false;
        //workaorund
        e.Row.IsSelected = false;
        e.Row.IsCurrent = false;
    }
}