private async void Button_ClickAsync(object sender, RoutedEventArgs e)
        //GUZIK WYKRESY
        {
            if (authorController.Empty())
            {
                DisplayNoSignaturesDialog();
                return;
            }
            CoreApplicationView newView = CoreApplication.CreateNewView();
            int newViewId = 0;
            await newView.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                Frame frame    = new Frame();
                var signatures = this.signatureController.getSignatures();
                frame.Navigate(typeof(ShowSignatures), authorController);
                Window.Current.Content = frame;
                // You have to activate the window in order to show it later.
                Window.Current.Activate();

                newViewId = ApplicationView.GetForCurrentView().Id;
            });

            bool viewShown = await ApplicationViewSwitcher.TryShowAsStandaloneAsync(newViewId);
        }