function MessageDialog(const Msg: String; MsgDlgType: TMsgDlgType;
  const MsgDlgButtons: TMsgDlgButtons; const Caption: String): TModalResult;
var
  MessageForm: TForm;
begin
  MessageForm := CreateMessageDialog(Msg, MsgDlgType, MsgDlgButtons);
  MessageForm.BorderIcons := [];
  if Caption = '' then
    MessageForm.Caption := Application.Title
  else
    MessageForm.Caption := Caption;
  MessageForm.Position := poDesktopCenter;
  Result := MessageForm.ShowModal;
  MessageForm.Release;
end;