public MainWindowViewModel()
        {
            ApplicationMessageService = new ApplicationMessageServiceViewModel();
            CompositeDisposable.Add(ApplicationMessageService);

            SettingsViewModel = new SettingsViewModel();
            CompositeDisposable.Add(SettingsViewModel);
        }
 public LoginWindowViewModel()
 {
     AuthorizerViewModel = new AuthorizerViewModel();
     ApplicationMessageService = new ApplicationMessageServiceViewModel();
     CompositeDisposable.Add(ApplicationMessageService);
 }
 public MessageWindowViewModel()
 {
     ApplicationMessageServiceViewModel = new ApplicationMessageServiceViewModel();
     CompositeDisposable.Add(ApplicationMessageServiceViewModel);
 }