Fix: Fixed issue where tabs weren't restored when resuming from the background (#14857)

Author: yaira2

src/Files.App/App.xaml.cs

@@ -208,6 +208,7 @@ private async void Window_Closed(object sender, WindowEventArgs args)
 				return;
 			}
 
+			// Save the current tab list in case it was overwriten by another instance
 			AppLifecycleHelper.SaveSessionTabs();
 
 			// Continue running the app on the background

src/Files.App/Data/Contexts/Multitasking/MultitaskingContext.cs

@@ -39,7 +39,6 @@ public MultitaskingContext()
 		private void AppInstances_CollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
 		{
 			UpdateTabCount();
-			AppLifecycleHelper.SaveSessionTabs();
 		}
 		private void AppModel_PropertyChanged(object? sender, PropertyChangedEventArgs e)
 		{

src/Files.App/Helpers/Application/AppLifecycleHelper.cs

@@ -282,6 +282,7 @@ public static void HandleAppUnhandledException(Exception? ex, bool showToastNoti
 			// Please check "Output Window" for exception details (View -> Output Window) (CTRL + ALT + O)
 			Debugger.Break();
 
+			// Save the current tab list in case it was overwriten by another instance
 			SaveSessionTabs();
 			App.Logger.LogError(ex, ex?.Message ?? "An unhandled error occurred.");
 

src/Files.App/Helpers/Navigation/NavigationHelpers.cs

@@ -61,6 +61,9 @@ public static async Task AddNewTabByPathAsync(Type type, string? path, int atInd
 			MainPageViewModel.AppInstances.Insert(index, tabItem);
 
 			App.AppModel.TabStripSelectedIndex = index;
+
+			// Save the updated tab list
+			AppLifecycleHelper.SaveSessionTabs();
 		}
 
 		public static async Task AddNewTabByParamAsync(Type type, object tabViewItemArgs, int atIndex = -1)
@@ -86,6 +89,9 @@ public static async Task AddNewTabByParamAsync(Type type, object tabViewItemArgs
 			var index = atIndex == -1 ? MainPageViewModel.AppInstances.Count : atIndex;
 			MainPageViewModel.AppInstances.Insert(index, tabItem);
 			App.AppModel.TabStripSelectedIndex = index;
+
+			// Save the updated tab list
+			AppLifecycleHelper.SaveSessionTabs();
 		}
 
 		private static async Task UpdateTabInfoAsync(TabBarItem tabItem, object navigationArg)

src/Files.App/Services/UpdateService.cs

@@ -109,8 +109,11 @@ public async Task CheckForUpdatesAsync()
 
 		private async Task DownloadAndInstallAsync()
 		{
+			// Save the updated tab list before installing the update
 			AppLifecycleHelper.SaveSessionTabs();
+
 			App.AppModel.ForceProcessTermination = true;
+
 			var downloadOperation = _storeContext?.RequestDownloadAndInstallStorePackageUpdatesAsync(_updatePackages);
 			var result = await downloadOperation.AsTask();
 

src/Files.App/UserControls/TabBar/BaseTabBar.cs

@@ -147,6 +147,9 @@ public void CloseTab(TabBarItem tabItem)
 				tabItem.NavigationParameter,
 			});
 
+			// Save the updated tab list
+			AppLifecycleHelper.SaveSessionTabs();
+
 			if (Items.Count == 0)
 				MainWindow.Instance.Close();
 		}

src/Files.App/ViewModels/Settings/GeneralViewModel.cs

@@ -114,10 +114,17 @@ public GeneralViewModel()
 
 		private async void DoRestartAsync()
 		{
-			UserSettingsService.AppSettingsService.RestoreTabsOnStartup = true; // Tells the app to restore tabs when it's next launched
-			AppLifecycleHelper.SaveSessionTabs(); // Saves the open tabs
-			await Launcher.LaunchUriAsync(new Uri("files-uwp:")); // Launches a new instance of Files
-			Process.GetCurrentProcess().Kill(); // Closes the current instance
+			// Tells the app to restore tabs when it's next launched
+			UserSettingsService.AppSettingsService.RestoreTabsOnStartup = true;
+
+			// Save the updated tab list before restarting
+			AppLifecycleHelper.SaveSessionTabs();
+
+			// Launches a new instance of Files
+			await Launcher.LaunchUriAsync(new Uri("files-uwp:"));
+
+			// Closes the current instance
+			Process.GetCurrentProcess().Kill();
 		}
 
 		private void DoCancelRestart()