How to hide the row headers of the ChildTable in the WinForms GridGroupingControl?

//Gets the ChildTable Model in the Form_Load.
GridTableModel tbl = this.gridGroupingControl1.GetTableModel("ChildTable");
//Hooks the QueryColWidth event to change the width of the Child Table row header.
tbl.QueryColWidth += new GridRowColSizeEventHandler(tbl_QueryColWidth);
//Child Table QueryColWidth event Handler.
private void tbl_QueryColWidth(object sender, GridRowColSizeEventArgs e)
{
   //Checks the col index == 0 to identify.
   if(e.Index == 0)
   {
      //Sets the size of the RowHeader width to zero.
      e.Size = 0;
      e.Handled = true;
   }
}

'Gets the ChildTable Model in the Form_Load.
Private tbl As GridTableModel = Me.gridGroupingControl1.GetTableModel("ChildTable")
'Hooks the QueryColWidth event to change the width of the Child Table row header.
Private tbl.QueryColWidth += New GridRowColSizeEventHandler(AddressOf tbl_QueryColWidth)
'Child Table QueryColWidth event Handler.
Private Sub tbl_QueryColWidth(ByVal sender As Object, ByVal e As GridRowColSizeEventArgs)
   'Checks the col index == 0 to identify. 
   If e.Index = 0 Then
      'Sets the size of the RowHeader width to zero.
      e.Size = 0
      e.Handled = True
   End If
End Sub