diff --git a/Sources/AppDelegate.swift b/Sources/AppDelegate.swift
index 5b0c9cb2..aaf0fe05 100644
--- a/Sources/AppDelegate.swift
+++ b/Sources/AppDelegate.swift
@@ -9,6 +9,30 @@ import Combine
 import ObjectiveC.runtime
 import Darwin
 
+final class MainWindowHostingView<Content: View>: NSHostingView<Content> {
+    private let zeroSafeAreaLayoutGuide = NSLayoutGuide()
+
+    override var safeAreaInsets: NSEdgeInsets { NSEdgeInsetsZero }
+    override var safeAreaRect: NSRect { bounds }
+    override var safeAreaLayoutGuide: NSLayoutGuide { zeroSafeAreaLayoutGuide }
+
+    required init(rootView: Content) {
+        super.init(rootView: rootView)
+        addLayoutGuide(zeroSafeAreaLayoutGuide)
+        NSLayoutConstraint.activate([
+            zeroSafeAreaLayoutGuide.leadingAnchor.constraint(equalTo: leadingAnchor),
+            zeroSafeAreaLayoutGuide.trailingAnchor.constraint(equalTo: trailingAnchor),
+            zeroSafeAreaLayoutGuide.topAnchor.constraint(equalTo: topAnchor),
+            zeroSafeAreaLayoutGuide.bottomAnchor.constraint(equalTo: bottomAnchor),
+        ])
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
 private enum CmuxThemeNotifications {
     static let reloadConfig = Notification.Name("com.cmuxterm.themes.reload-config")
 }
@@ -5457,7 +5481,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         } else {
             window.center()
         }
-        window.contentView = NSHostingView(rootView: root)
+        window.contentView = MainWindowHostingView(rootView: root)
 
         // Apply shared window styling.
         attachUpdateAccessory(to: window)
diff --git a/Sources/Update/UpdateTitlebarAccessory.swift b/Sources/Update/UpdateTitlebarAccessory.swift
index cd18fb56..0b9c956c 100644
--- a/Sources/Update/UpdateTitlebarAccessory.swift
+++ b/Sources/Update/UpdateTitlebarAccessory.swift
@@ -1173,6 +1173,7 @@ private struct NotificationPopoverRow: View {
     }
 }
 
+@MainActor
 final class UpdateTitlebarAccessoryController {
     private weak var updateViewModel: UpdateViewModel?
     private var didStart = false
@@ -1213,7 +1214,9 @@ final class UpdateTitlebarAccessoryController {
             queue: .main
         ) { [weak self] notification in
             guard let window = notification.object as? NSWindow else { return }
-            self?.attachIfNeeded(to: window)
+            Task { @MainActor [weak self] in
+                self?.attachIfNeeded(to: window)
+            }
         })
 
         observers.append(center.addObserver(
@@ -1222,7 +1225,9 @@ final class UpdateTitlebarAccessoryController {
             queue: .main
         ) { [weak self] notification in
             guard let window = notification.object as? NSWindow else { return }
-            self?.attachIfNeeded(to: window)
+            Task { @MainActor [weak self] in
+                self?.attachIfNeeded(to: window)
+            }
         })
 
         // We intentionally do not rely on "window became visible" notifications here:
@@ -1242,7 +1247,9 @@ final class UpdateTitlebarAccessoryController {
         let delays: [TimeInterval] = [0.05, 0.15, 0.3, 0.6, 1.0, 2.0, 3.0]
         for delay in delays {
             let item = DispatchWorkItem { [weak self] in
-                self?.attachToExistingWindows()
+                Task { @MainActor [weak self] in
+                    self?.attachToExistingWindows()
+                }
 #if DEBUG
                 let env = ProcessInfo.processInfo.environment
                 if env["CMUX_UI_TEST_MODE"] == "1" {
@@ -1258,7 +1265,6 @@ final class UpdateTitlebarAccessoryController {
     }
 
     private func attachIfNeeded(to window: NSWindow) {
-        guard !attachedWindows.contains(window) else { return }
         guard !isSettingsWindow(window) else { return }
 
         // Window identifiers are assigned by SwiftUI via WindowAccessor, which can run
@@ -1270,8 +1276,10 @@ final class UpdateTitlebarAccessoryController {
             if attempts < 40 {
                 pendingAttachRetries[key] = attempts + 1
                 DispatchQueue.main.asyncAfter(deadline: .now() + 0.05) { [weak self, weak window] in
-                    guard let self, let window else { return }
-                    self.attachIfNeeded(to: window)
+                    Task { @MainActor [weak self, weak window] in
+                        guard let self, let window else { return }
+                        self.attachIfNeeded(to: window)
+                    }
                 }
             } else {
                 pendingAttachRetries.removeValue(forKey: key)
@@ -1281,6 +1289,13 @@ final class UpdateTitlebarAccessoryController {
 
         pendingAttachRetries.removeValue(forKey: ObjectIdentifier(window))
 
+        guard WorkspaceTitlebarSettings.isVisible() else {
+            removeAccessoryIfPresent(from: window)
+            return
+        }
+
+        guard !attachedWindows.contains(window) else { return }
+
         if !window.titlebarAccessoryViewControllers.contains(where: { $0.view.identifier == controlsIdentifier }) {
             let controls = TitlebarControlsAccessoryViewController(
                 notificationStore: TerminalNotificationStore.shared
@@ -1302,6 +1317,40 @@ final class UpdateTitlebarAccessoryController {
 #endif
     }
 
+    private func removeAccessoryIfPresent(from window: NSWindow) {
+        let matchingIndices = window.titlebarAccessoryViewControllers.indices.reversed().filter { index in
+            window.titlebarAccessoryViewControllers[index].view.identifier == controlsIdentifier
+        }
+        guard !matchingIndices.isEmpty || attachedWindows.contains(window) else { return }
+
+        for index in matchingIndices {
+            let accessory = window.titlebarAccessoryViewControllers[index]
+            if let controls = accessory as? TitlebarControlsAccessoryViewController {
+                controls.dismissNotificationsPopover()
+            }
+            window.removeTitlebarAccessoryViewController(at: index)
+        }
+
+        attachedWindows.remove(window)
+        pendingAttachRetries.removeValue(forKey: ObjectIdentifier(window))
+        DispatchQueue.main.async { [weak window] in
+            guard let window else { return }
+            window.contentView?.needsLayout = true
+            window.contentView?.superview?.needsLayout = true
+            window.contentView?.layoutSubtreeIfNeeded()
+            window.contentView?.superview?.layoutSubtreeIfNeeded()
+            window.invalidateShadow()
+        }
+
+#if DEBUG
+        let env = ProcessInfo.processInfo.environment
+        if env["CMUX_UI_TEST_MODE"] == "1" {
+            let ident = window.identifier?.rawValue ?? "<nil>"
+            UpdateLogStore.shared.append("removed titlebar accessories from window id=\(ident)")
+        }
+#endif
+    }
+
     private func isSettingsWindow(_ window: NSWindow) -> Bool {
         if window.identifier?.rawValue == "cmux.settings" {
             return true
diff --git a/Sources/cmuxApp.swift b/Sources/cmuxApp.swift
index 3da2656d..ea6c3e35 100644
--- a/Sources/cmuxApp.swift
+++ b/Sources/cmuxApp.swift
@@ -3241,6 +3241,16 @@ struct SettingsView: View {
         )
     }
 
+    private var showWorkspaceTitlebarBinding: Binding<Bool> {
+        Binding(
+            get: { showWorkspaceTitlebar },
+            set: { newValue in
+                showWorkspaceTitlebar = newValue
+                reassertSettingsWindowFocusIfNeeded()
+            }
+        )
+    }
+
     private var settingsSidebarTintLightBinding: Binding<Color> {
         Binding(
             get: {
@@ -3590,9 +3600,10 @@ struct SettingsView: View {
                             String(localized: "settings.app.showWorkspaceTitlebar", defaultValue: "Show Workspace Title Bar"),
                             subtitle: workspaceTitlebarSubtitle
                         ) {
-                            Toggle("", isOn: $showWorkspaceTitlebar)
+                            Toggle("", isOn: showWorkspaceTitlebarBinding)
                                 .labelsHidden()
                                 .controlSize(.small)
+                                .accessibilityIdentifier("SettingsShowWorkspaceTitlebarToggle")
                                 .accessibilityLabel(
                                     String(localized: "settings.app.showWorkspaceTitlebar", defaultValue: "Show Workspace Title Bar")
                                 )
@@ -4625,6 +4636,19 @@ struct SettingsView: View {
         NSApplication.shared.terminate(nil)
     }
 
+    private func reassertSettingsWindowFocusIfNeeded() {
+        DispatchQueue.main.async {
+            guard let window = SettingsWindowController.shared.window, window.isVisible else { return }
+            window.orderFrontRegardless()
+            window.makeKeyAndOrderFront(nil)
+            DispatchQueue.main.async {
+                guard window.isVisible else { return }
+                window.orderFrontRegardless()
+                window.makeKeyAndOrderFront(nil)
+            }
+        }
+    }
+
     private func resetAllSettings() {
         isResettingSettings = true
         appLanguage = LanguageSettings.defaultLanguage.rawValue