Attachment with MailMessage Component

I found following code for sending an e-mail with the Indy component MailMessage:

First time I send an e-mail with an attachment it is OK, but second time the e-mail sent is attached the same file twice. And the third time I send an e-mail it is attached with the same e-mail three times.

But when I close the application and send an e-mail the file is only attached once.
So why do I have do close my application to avoid the many attachments with the same file?


procedure TMailerForm.btnSendMailClick(Sender: TObject);
begin
  StatusMemo.Clear;

  //setup SMTP
  SMTP.Host := ledHost.Text;
  SMTP.Port := 25;

  //setup mail message
  MailMessage.From.Address := ledFrom.Text;
  MailMessage.Recipients.EMailAddresses := ledTo.Text + ',' + ledCC.Text;

  MailMessage.Subject := ledSubject.Text;
  MailMessage.Body.Text := Body.Text;

  if FileExists(ledAttachment.Text) then
    TIdAttachment.Create(MailMessage.MessageParts, ledAttachment.Text);

  //send mail
  try
    try
      SMTP.Connect(1000);
      SMTP.Send(MailMessage);
    except on E:Exception do
      StatusMemo.Lines.Insert(0, 'ERROR: ' + E.Message);
    end;
  finally
    if SMTP.Connected then SMTP.Disconnect;
  end;

end; (* btnSendMail Click *)