Bind the grid to the following DataTable:

            DataTable dt = new DataTable();     
            dt.Columns.Add("X.Y"); 
            dt.Columns.Add("X");   
            
            dt.Rows.Add("Data X.Y", "Data X");

            this.radGridView1.DataSource = dt;

You will notice that the second column "X" is missing.

Note: if you change the order of adding the columns, both columns will be added.