Lazarus identifica titolo colonna cliccato

procedure TForm2.DBGrid1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
  var
  Col,
  Row : Integer;
begin
  Col := DBGrid1.MouseCoord(X, Y).X;
  Row := DBGrid1.MouseCoord(X, Y).Y;
  if (dgIndicator in DBGrid1.Options) then
    Dec(Col);
  if (Col >= 0) and (Col < DBGrid1.Columns.Count) and (Y < DBGrid1.DefaultRowHeight) then
    if Button = mbRight then
    begin
      case DBGrid1.Columns[Col].Title.Caption of
        'SURNAME':
          showmessage('cliccato sur');
        'STUDENT_NO':
          showmessage('cliccato sutdent no');
        'FORENAME':
          showmessage('worka, wow');
      end;
    //Caption := DBGrid1.Columns[Col].Title.Caption
    end
  else
    Caption := '';
end;