fix(mac): show the menu bar item with an AppKit status item

App/MenuBarController.swift

@@ -0,0 +1,124 @@
+import AppKit
+import Observation
+import SwiftUI
+
+/// The StudyApp item in the menu bar, built with AppKit (`NSStatusItem` and a popover).
+///
+/// SwiftUI's `MenuBarExtra` scene kept the app's scene graph changing at launch, so the main
+/// window rebuilt its toolbar endlessly and the app hung. A status item owned by the app avoids
+/// the extra scene; the popover still shows the SwiftUI `MenuBarContent`.
+@MainActor
+final class MenuBarController: NSObject {
+    private let calendar: StudyCalendarViewModel
+    private let today: TodayViewModel
+    private let navigation: AppNavigation
+    private let defaults: UserDefaults
+    private var statusItem: NSStatusItem?
+    private var defaultsObserver: NSObjectProtocol?
+    private lazy var popover: NSPopover = makePopover()
+
+    init(
+        calendar: StudyCalendarViewModel,
+        today: TodayViewModel,
+        navigation: AppNavigation,
+        defaults: UserDefaults = .standard
+    ) {
+        self.calendar = calendar
+        self.today = today
+        self.navigation = navigation
+        self.defaults = defaults
+    }
+
+    /// Shows the item when the setting is on and follows later changes of the setting.
+    func install() {
+        guard defaultsObserver == nil else { return }
+        defaultsObserver = NotificationCenter.default.addObserver(
+            forName: UserDefaults.didChangeNotification, object: defaults, queue: .main
+        ) { [weak self] _ in
+            MainActor.assumeIsolated { self?.applyVisibility() }
+        }
+        applyVisibility()
+    }
+
+    // MARK: Visibility
+
+    private var isEnabled: Bool {
+        defaults.object(forKey: ViewPreferences.showsMenuBarItemKey) as? Bool ?? true
+    }
+
+    private func applyVisibility() {
+        if isEnabled, statusItem == nil {
+            let item = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
+            item.button?.target = self
+            item.button?.action = #selector(togglePopover(_:))
+            item.button?.imagePosition = .imageLeading
+            statusItem = item
+            observeSummary()
+        } else if !isEnabled, let item = statusItem {
+            popover.performClose(nil)
+            NSStatusBar.system.removeStatusItem(item)
+            statusItem = nil
+        }
+    }
+
+    // MARK: Label
+
+    /// Updates the label now and again whenever the lecture or the due cards change.
+    private func observeSummary() {
+        guard statusItem != nil else { return }
+        let summary = withObservationTracking {
+            MenuBarSummary(calendar: calendar, dueCards: today.totalDue)
+        } onChange: { [weak self] in
+            Task { @MainActor in self?.observeSummary() }
+        }
+        updateLabel(summary)
+    }
+
+    private func updateLabel(_ summary: MenuBarSummary) {
+        guard let button = statusItem?.button else { return }
+        let symbol = summary.title.isEmpty ? "graduationcap" : "record.circle"
+        button.image = NSImage(systemSymbolName: symbol, accessibilityDescription: "StudyApp")
+        button.title = summary.title.isEmpty ? "" : " \(summary.title)"
+    }
+
+    // MARK: Popover
+
+    @objc private func togglePopover(_ sender: NSStatusBarButton) {
+        if popover.isShown {
+            popover.performClose(sender)
+        } else {
+            popover.show(relativeTo: sender.bounds, of: sender, preferredEdge: .minY)
+            popover.contentViewController?.view.window?.makeKey()
+        }
+    }
+
+    private func makePopover() -> NSPopover {
+        let popover = NSPopover()
+        popover.behavior = .transient
+        popover.contentViewController = NSHostingController(rootView: MenuBarPopoverView(
+            calendar: calendar,
+            today: today,
+            onOpenLecture: { [weak self] moduleID in
+                self?.openMainWindow()
+                self?.navigation.show(module: moduleID, section: .slides, intent: .resumeSlides)
+            },
+            onReviewCards: { [weak self] in
+                guard let self else { return }
+                openMainWindow()
+                // Starts with the module that has the most due cards, like „Lernen starten“ on Today.
+                if let moduleID = today.dueCounts.max(by: { $0.value < $1.value })?.key {
+                    navigation.show(module: moduleID, section: .flashcards)
+                }
+            },
+            onOpenApp: { [weak self] in self?.openMainWindow() }
+        ))
+        return popover
+    }
+
+    /// Closes the popover and brings the main window to the front.
+    private func openMainWindow() {
+        popover.performClose(nil)
+        NSApplication.shared.activate()
+        NSApplication.shared.windows.first { $0.canBecomeMain }?.makeKeyAndOrderFront(nil)
+    }
+}

App/StudyAppApp.swift

@@ -8,6 +8,7 @@ struct StudyAppApp: App {
     private let autopilot: LectureAutopilot
     /// Installed in `init` so a click that launches the app is not lost.
     private let notificationResponder: NotificationResponder
+    private let menuBar: MenuBarController
     @State private var modulesViewModel: ModulesViewModel
     @State private var calendarViewModel: StudyCalendarViewModel
     @State private var todayViewModel: TodayViewModel
@@ -22,7 +23,6 @@ struct StudyAppApp: App {
     @State private var mensaViewModel: MensaViewModel
     @State private var updater = AppUpdater()
     @AppStorage(ViewPreferences.appearanceKey) private var appearance = AppAppearance.standard
-    @AppStorage(ViewPreferences.showsMenuBarItemKey) private var showsMenuBarItem = true
 
     init() {
         do {
@@ -33,6 +33,7 @@ struct StudyAppApp: App {
             let assignments = container.makeAssignmentsViewModel()
             let exams = container.makeExamsViewModel()
             let navigation = AppNavigation()
+            menuBar = MenuBarController(calendar: calendar, today: today, navigation: navigation)
             let studIP = container.makeStudIPViewModel()
             let announcements = container.makeAnnouncementsViewModel()
             studIP.onAnnouncementsSynced = { announcements.load() }
@@ -155,33 +156,6 @@ struct StudyAppApp: App {
             BackupCommands(viewModel: backupViewModel)
         }
 
-        MenuBarExtra(isInserted: $showsMenuBarItem) {
-            MenuBarSummaryReader(calendar: calendarViewModel, today: todayViewModel) { summary in
-                MenuBarContent(
-                    summary: summary,
-                    onOpenLecture: { moduleID in
-                        Self.bringToFront()
-                        navigation.show(module: moduleID, section: .slides, intent: .resumeSlides)
-                    },
-                    onReviewCards: {
-                        Self.bringToFront()
-                        // Starts with the module that has the most due cards, like „Lernen starten“ on Today.
-                        if let moduleID = todayViewModel.dueCounts.max(by: { $0.value < $1.value })?.key {
-                            navigation.show(module: moduleID, section: .flashcards)
-                        }
-                    },
-                    onOpenApp: { Self.bringToFront() }
-                )
-                .tint(Theme.accent)
-                .preferredColorScheme(appearance.colorScheme)
-            }
-        } label: {
-            MenuBarSummaryReader(calendar: calendarViewModel, today: todayViewModel) { summary in
-                MenuBarLabel(summary: summary)
-            }
-        }
-        .menuBarExtraStyle(.window)
-
         Settings {
             SettingsView(
                 settings: container.preferences,
@@ -210,6 +184,7 @@ struct StudyAppApp: App {
         if navigation.destination == nil {
             navigation.showToday()
         }
+        menuBar.install()
         autopilot.run(isLaunch: true)
 
         // Abonnements im Hintergrund auffrischen; eine dabei neu erkannte Vorlesung wird ebenfalls geöffnet.
@@ -223,12 +198,6 @@ struct StudyAppApp: App {
         await notificationsViewModel.refresh()
     }
 
-    /// Shows the main window, e.g. after a click in the menu bar.
-    private static func bringToFront() {
-        NSApplication.shared.activate()
-        NSApplication.shared.windows.first { $0.canBecomeMain }?.makeKeyAndOrderFront(nil)
-    }
-
     /// Keeps Spotlight in line with notes and study sheets; failures only cost search results.
     private func reindexSearch() async {
         try? await container.makeReindexSearch()()

Presentation/MenuBar/MenuBarContent.swift

@@ -1,29 +1,25 @@
 import AppKit
 import SwiftUI
 
-/// Builds the summary inside a view, so only the menu bar item observes the calendar and the due cards.
-/// Reading them in the App body would rebuild every scene on each change, already while the app launches.
-struct MenuBarSummaryReader<Content: View>: View {
+/// Content of the menu bar popover: builds the summary inside the view, so it follows the calendar
+/// and the due cards, and applies the chosen appearance.
+struct MenuBarPopoverView: View {
     let calendar: StudyCalendarViewModel
     let today: TodayViewModel
-    @ViewBuilder let content: (MenuBarSummary) -> Content
-
-    var body: some View {
-        content(MenuBarSummary(calendar: calendar, dueCards: today.totalDue))
-    }
-}
-
-/// The menu bar item's label: an icon, plus the remaining minutes while a lecture runs.
-struct MenuBarLabel: View {
-    let summary: MenuBarSummary
+    let onOpenLecture: (UUID) -> Void
+    let onReviewCards: () -> Void
+    let onOpenApp: () -> Void
+    @AppStorage(ViewPreferences.appearanceKey) private var appearance = AppAppearance.standard
 
     var body: some View {
-        if summary.title.isEmpty {
-            Image(systemName: "graduationcap")
-        } else {
-            Label(summary.title, systemImage: "record.circle")
-                .labelStyle(.titleAndIcon)
-        }
+        MenuBarContent(
+            summary: MenuBarSummary(calendar: calendar, dueCards: today.totalDue),
+            onOpenLecture: onOpenLecture,
+            onReviewCards: onReviewCards,
+            onOpenApp: onOpenApp
+        )
+        .tint(Theme.accent)
+        .preferredColorScheme(appearance.colorScheme)
     }
 }
 

docs/ARCHITECTURE.md

@@ -34,7 +34,7 @@ Dependencies point **inward**: Presentation and Data both depend on Domain, Doma
 
 `AppContainer(inMemory: true)` swaps in in-memory persistence and preferences for previews and tests.
 
-`AppLauncher` is the entry point: under XCTest it starts an empty host app instead of `StudyAppApp`, so launch work (database, sync, menu bar item) never runs during unit tests. On CI runners the menu bar scene kept the test host from finishing its launch.
+`AppLauncher` is the entry point: under XCTest it starts an empty host app instead of `StudyAppApp`, so launch work (database, sync, menu bar item) never runs during unit tests. This keeps the unit tests independent of the window, the menu bar item and the network.
 
 ## Data flow example: calendar subscription → module
 

docs/FEATURES.md

@@ -84,7 +84,9 @@ Code: `Presentation/StudIP/`, `Domain/UseCases/StudIPUseCases.swift`, `Data/Stud
 
 The menu bar item shows the remaining minutes while a lecture runs. Its window lists the running or next lecture (with „Folien öffnen“) and the due flashcards, and opens the main window. It can be hidden in Settings → Allgemein.
 
-Code: `Presentation/MenuBar/`
+The item is an AppKit `NSStatusItem` with a popover (`App/MenuBarController.swift`), not a SwiftUI `MenuBarExtra` scene: that scene kept the scene graph changing at launch and the app hung.
+
+Code: `App/MenuBarController.swift`, `Presentation/MenuBar/`
 
 ## Shortcuts and Siri