Différencier les 3 bouttons de la souris

procedure TForm1.Panel1MouseDown(Sender: TObject; Button: TMouseButton;
Sh if t: TSh if tState; X, Y: Integer);
begin
if Button = mbRight then Showmessage('Click droit')
else If Button = mbMiddle then Showmessage('Click milieu')
else if button = mbleft then Showmessage('Click gauche');
end;