Several fixes for continue where you left off (#1792)

Author: d2dyno1

Files/App.xaml.cs

@@ -415,7 +415,7 @@ private void OnSuspending(object sender, SuspendingEventArgs e)
 
         private void SaveSessionTabs() // Enumerates through all tabs and gets the Path property and saves it to AppSettings.LastSessionPages
         {
-            AppSettings.LastSessionPages = MainPage.AppInstances.Select(x => x.Path ?? ResourceController.GetTranslation("NewTab")).ToArray();
+            AppSettings.LastSessionPages = MainPage.AppInstances.DefaultIfEmpty().Select(x => x != null ? x.Path : ResourceController.GetTranslation("NewTab")).ToArray();
         }
 
         // Occurs when an exception is not handled on the UI thread.

Files/UserControls/MultitaskingControl/HorizontalMultitaskingControl.xaml.cs

@@ -343,6 +343,7 @@ private async void RemoveTab(TabItem tabItem)
         {
             if (Items.Count == 1)
             {
+                MainPage.AppInstances.Remove(tabItem);
                 await ApplicationView.GetForCurrentView().TryConsolidateAsync();
             }
             else if (Items.Count > 1)

Files/UserControls/MultitaskingControl/VerticalTabView.xaml.cs

@@ -333,6 +333,7 @@ private void RemoveTab(TabItem tabItem)
         {
             if (Items.Count == 1)
             {
+                MainPage.AppInstances.Remove(tabItem);
                 App.CloseApp();
             }
             else if (Items.Count > 1)

Files/Views/MainPage.xaml.cs

@@ -111,6 +111,7 @@ protected override async void OnNavigatedTo(NavigationEventArgs eventArgs)
                                 {
                                     await AddNewTab(typeof(ModernShellPage), path);
                                 }
+                                App.AppSettings.LastSessionPages = new string[] { ResourceController.GetTranslation("NewTab") };
                             }
                             else
                             {