At WWDC25 we launched a new type of Lab event for the developer community - Group Labs. A Group Lab is a panel Q&A designed for a large audience of developers. Group Labs are a unique opportunity for the community to submit questions directly to a panel of Apple engineers and designers. Here are the highlights from the WWDC25 Group Lab for UI Frameworks. How would you recommend developers start adopting the new design? Start by focusing on the foundational structural elements of your application, working from the "top down" or "bottom up" based on your application's hierarchy. These structural changes, like edge-to-edge content and updated navigation and controls, often require corresponding code modifications. As a first step, recompile your application with the new SDK to see what updates are automatically applied, especially if you've been using standard controls. Then, carefully analyze where the new design elements can be applied to your UI, paying particular attention to custom controls or UI that could benefit from a refresh. Address the large structural items first then focus on smaller details is recommended. Will we need to migrate our UI code to Swift and SwiftUI to adopt the new design? No, you will not need to migrate your UI code to Swift and SwiftUI to adopt the new design. The UI frameworks fully support the new design, allowing you to migrate your app with as little effort as possible, especially if you've been using standard controls. The goal is to make it easy to adopt the new design, regardless of your current UI framework, to achieve a cohesive look across the operating system. What was the reason for choosing Liquid Glass over frosted glass, as used in visionOS? The choice of Liquid Glass was driven by the desire to bring content to life. The see-through nature of Liquid Glass enhances this effect. The appearance of Liquid Glass adapts based on its size; larger glass elements look more frosted, which aligns with the design of visionOS, where everything feels larger and benefits from the frosted look. What are best practices for apps that use customized navigation bars? The new design emphasizes behavior and transitions as much as static appearance. Consider whether you truly need a custom navigation bar, or if the system-provided controls can meet your needs. Explore new APIs for subtitles and custom views in navigation bars, designed to support common use cases. If you still require a custom solution, ensure you're respecting safe areas using APIs like SwiftUI's safeAreaInset. When working with Liquid Glass, group related buttons in shared containers to maintain design consistency. Finally, mark glass containers as interactive. For branding, instead of coloring the navigation bar directly, consider incorporating branding colors into the content area behind the Liquid Glass controls. This creates a dynamic effect where the color is visible through the glass and moves with the content as the user scrolls. I want to know why new UI Framework APIs aren’t backward compatible, specifically in SwiftUI? It leads to code with lots of if-else statements. Existing APIs have been updated to work with the new design where possible, ensuring that apps using those APIs will adopt the new design and function on both older and newer operating systems. However, new APIs often depend on deep integration across the framework and graphics stack, making backward compatibility impractical. When using these new APIs, it's important to consider how they fit within the context of the latest OS. The use of if-else statements allows you to maintain compatibility with older systems while taking full advantage of the new APIs and design features on newer systems. If you are using new APIs, it likely means you are implementing something very specific to the new design language. Using conditional code allows you to intentionally create different code paths for the new design versus older operating systems. Prefer to use if #available where appropriate to intentionally adopt new design elements. Are there any Liquid Glass materials in iOS or macOS that are only available as part of dedicated components? Or are all those materials available through new UIKit and AppKit views? Yes, some variations of the Liquid Glass material are exclusively available through dedicated components like sliders, segmented controls, and tab bars. However, the "regular" and "clear" glass materials should satisfy most application requirements. If you encounter situations where these options are insufficient, please file feedback. If I were to create an app today, how should I design it to make it future proof using Liquid Glass? The best approach to future-proof your app is to utilize standard system controls and design your UI to align with the standard system look and feel. Using the framework-provided declarative API generally leads to easier adoption of future design changes, as you're expressing intent rather than specifying pixel-perfect visuals. Pay close attention to the design sessions offered this year, which cover the design motivation behind the Liquid Glass material and best practices for its use. Is it possible to implement your own sidebar on macOS without NSSplitViewController, but still provide the Liquid Glass appearance? While technically possible to create a custom sidebar that approximates the Liquid Glass appearance without using NSSplitViewController, it is not recommended. The system implementation of the sidebar involves significant unseen complexity, including interlayering with scroll edge effects and fullscreen behaviors. NSSplitViewController provides the necessary level of abstraction for the framework to handle these details correctly. Regarding the SceneDelagate and scene based life-cycle, I would like to confirm that AppDelegate is not going away. Also if the above is a correct understanding, is there any advice as to what should, and should not, be moved to the SceneDelegate? UIApplicationDelegate is not going away and still serves a purpose for application-level interactions with the system and managing scenes at a higher level. Move code related to your app's scene or UI into the UISceneDelegate. Remember that adopting scenes doesn't necessarily mean supporting multiple scenes; an app can be scene-based but still support only one scene. Refer to the tech note Migrating to the UIKit scene-based life cycle and the Make your UIKit app more flexible WWDC25 session for more information.

I am adopting some of the new glass UI, but having to duplicate a lot of code to maintain support for previous UI systems in macOS. An example: if #available(macOS 26.0, *) { VStack { /*some 40+ lines of code clipped here for brevity*/ } .cueButtons() .cueStyleGlass() } else { VStack { /*identical 40+ lines of code clipped here for brevity*/ } .cueButtons() .cueStyle() } If I try to use conditional modifiers as indicated here: extension View { func cueStyle(font: Font = .system(size: 45)) -> some View { if #available(macOS 26.0, *) { modifier(GlassCueStyle(font: font)) } else { modifier(CueStyle(font: font)) } } } I get this error: Conflicting arguments to generic parameter 'τ_1_0' ('ModifiedContent<Self, GlassCueStyle>' vs. 'ModifiedContent<Self, CueStyle>') Is there a better way to do this?

I just found a weird bug: If you place a Text view using .foregroundStyle(.secondary), .tertiary, or other semantic colors inside a ScrollView, and apply a Material background clipped to an UnevenRoundedRectangle, the text becomes invisible. This issue does not occur when: The text uses .primary or explicit colors (e.g., .red, Color.blue), or The background is clipped to a standard shape (e.g., RoundedRectangle). A minimal reproducible example is shown below: ScrollView{ VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello World.") .font(.system(size: 15)) .foregroundStyle(.quinary) } } .padding() .frame(height: 100) .background(Material.regular) .clipShape(UnevenRoundedRectangle(topLeadingRadius: 10,bottomLeadingRadius: 8,bottomTrailingRadius:8, topTrailingRadius: 8))

Hello, Developers! While writing custom view modifier I ran into unexpected behavior of .strokeBorder modifier. The underlying content seem to be “bleeding” outside of the stroke border edges, even though they share the exact same shape for their layout. This issue relevant for both Xcode Previews and on-device testing. Maybe someone has experienced this issue before, I'd be glad to see your opinion on this matter.

I reported Korean IME bug to QT Bug report. Please refer to below link. https://bugreports.qt.io/browse/QTBUG-136128?jql=text%20~%20korean%20ORDER%20BY%20created%20DESC But, QT reponsed me like follwing. Thank you for reporting. However, this issue seems like a known issue with apple's Korean IME. There are many threads in Korean community about the same problem with Non-Qt apps. If this issue is a really Qt issue, feel free to open it again. Is there any workaround to fix this IME bug ? Thanks, Ted

I'm struggling to understand whether TextField handles undo by itself, or how to properly handle it myself. In a macOS app with a SwiftUI lifecycle, in a DocumentGroup scene, I'm using both TextEditors and Textfields. The text editors handle undo out of the box, with undo coalescing. The text fields seem not to. However, on occasion, they do create undo points, leaving me confused as to what conditions are needed for that to happen. Is there a way to reliably get text fields to handle undo on their own? Or, how should I implement typing undo, including undo coalescing, manually?

I'd like to create a Quick Look extension for a file type for which a location or region on a Map should be shown as preview. However the MapView would only show a grid without any map. From within the MapKit delegate I can see from the "Error" parameter (a server with this domain can not be found) that this seems to be a network issue. The Quick Look extension seems to have no access to the internet and therefore the MapView can not load any map data. I've then also done some other tests via URLSession, which also only fails with connection errors. I haven't seen any limitations or restrictions mentioned in the API documentation. Is this the expected behavior? Is this a bug? Or am I missing something?

Why there is a working animation with ScrollView + ForEach of items removal, but there is none with List? ScrollView + ForEach: struct ContentView: View { @State var items: [String] = Array(1...5).map(\.description) var body: some View { ScrollView(.vertical) { ForEach(items, id: \.self) { item in Text(String(item)) .frame(maxWidth: .infinity, minHeight: 50) .background(.gray) .onTapGesture { withAnimation(.linear(duration: 0.1)) { items = items.filter { $0 != item } } } } } } } List: struct ContentView: View { @State var items: [String] = Array(1...5).map(\.description) var body: some View { List(items, id: \.self) { item in Text(String(item)) .frame(maxWidth: .infinity, minHeight: 50) .background(.gray) .onTapGesture { withAnimation(.linear(duration: 0.1)) { items = items.filter { $0 != item } } } } } }```

There is a problem with the launchscreen of my application on iPadOS 26. After release of the windowed mode feature the launchscreen of my fullscreen landscape-only application is being cropped and doesn't stretch to screen's size when the device is in the portrait mode. How can I fix this?

I had take screenshots by following code let scenes = UIApplication.shared.connectedScenes let windowScene = scenes.first as? UIWindowScene let window = windowScene?.windows.first self.uiImage = window?.rootViewController?.view!.getImage(rect: rect) View has two views. One is ImageView contains some image and overlay of image detection results with .overlay. another view is InfoView contains several info and button which above code fired. on iOS 17, I can take screenshots as I saw, but on iOS26, missing on image of ImageView. Overlay(detected rectangle) in Imageview and InfView can be taken. How can I take screenshots as I saw on iOS26?(iPad)

If I delete Safari and only have another browser installed on my device, UIApplication.shared.open does not work. I think this is a bug. Why would it not work? If Safari is not the main browser, UIApplication would open the URL in my main browser. Those are valid use cases. I would expect this API to work with any browser... iOS 26.2 iPhone 14 Pro guard let url = URL(string: "https://www.apple.com") else { return } if UIApplication.shared.canOpenURL(url) { UIApplication.shared.open(url) } else { print("Could not open URL") }

Environment iOS 26 (23A343) Xcode 26 Reproduces on device and Simulator Description When presenting a SwiftUI WebView (native iOS 26 component) or a WKWebView/UIWebView via UIViewRepresentable, focusing a text field inside the web view and then dismissing it breaks the keyboard layout behavior. After returning to the main app, tapping any TextField causes the keyboard to cover bottom controls (e.g. buttons). Expected safe area insets are not applied. The issue is only resolved after closing and reopening the keyboard once. Steps to Reproduce Open a SwiftUI screen with WebView (via .sheet or NavigationLink). Inside the web view, tap a text field to show the keyboard. Dismiss the web view. Tap a TextField in the main app. Expected Result Layout should adjust correctly. Bottom controls stay visible above the keyboard. Actual Result Keyboard covers bottom controls. Insets are ignored until the keyboard is dismissed and reopened. Notes Reproduces with: Native SwiftUI WebView (iOS 26) WKWebView and UIWebView via UIViewRepresentable Presentation style (.sheet or navigation push) does not matter. Example video: https://youtu.be/Epgoz1vETKU FB: FB20386257 Sample Code import SwiftUI import WebKit struct ContentView: View { @State var url: URL? @FocusState private var isFocused: Bool var body: some View { VStack { TextField("TextField", text: .constant("")) .focused($isFocused) Button("HIDE KEYBOARD") { isFocused = false } Spacer() Button("ACTION") { url = URL(string: "https://google.com") } } .sheet(item: $url) { value in NavigationStack { WebView(url: value) .toolbar { ToolbarItem(placement: .topBarLeading) { Button("CLOSE") { url = nil } } } } } } } extension URL: Identifiable { public var id: String { absoluteString } }

I’m seeing unexpected UITabBar behavior on iOS 26 when Liquid Glass is enabled. I’m using UITabBarAppearance with a dynamic UIColor to keep the selected tab bar icon and title text in sync (blue in light mode, green in dark mode). Expected behavior The selected tab bar icon and title text should always resolve to the same color based on the current trait collection. Actual behavior On initial load, the colors are correct. However, after switching light/dark mode (or any trait change that triggers a material update): The icon keeps the configured color The title text color is overridden by the system Result: selected icon and title text end up with different colors This happens even though both colors are explicitly set to the same dynamic UIColor. Minimal reproducible example: func applyAppearance() { let color = UIColor { trait in trait.userInterfaceStyle == .dark ? .green : .blue } self.tabBar.tintColor = color }

I'm trying to replicate edit/select mode of iOS 26 photos app. When user clicks Select button, bottom tab bar is replaced by the toolbar buttons. When I press Done button, a white opaque bar appears at the bottom behind the tabbar. It looks pretty straightforward to implement but I'm banging my head here now. Any help will be appreciated. Code and animation frames attached bellow struct ContentView: View { var body: some View { TabView(selection: $selectedTab) { OverviewView() .tabItem { Image(systemName: "chart.pie") Text("Overview") } .tag(0) //rest of the tabs } } } struct OverviewView: View { @State private var editActive = false @State private var selection = Set<String>() @State private var items = [ "Item 1", "Item 2", "Item 3", ] var body: some View { NavigationStack { List(selection: $selection) { ForEach(items, id: \.self) { item in Text(item) } } .toolbar { if editActive { ToolbarItem(placement: .bottomBar) { Button { } label: { Label("Delete", systemImage: "trash") } } ToolbarItem(placement: .bottomBar) { Button { } label: { Label("Category", systemImage: "tag") } } } ToolbarItem(placement: .topBarTrailing) { Button(editActive ? "Done" : "Select") { withAnimation { editActive.toggle() } } } } .environment(\.editMode, .constant(editActive ? .active : .inactive)) .toolbar(editActive ? .hidden : .visible, for: .tabBar) } } } I have attached 5 frames during animation phase.

iOS 26 SwiftUI .glassEffect() renders dark/gray on physical device - TestFlight doesn't fix it .glassEffect() renders as dark/muddy gray on my physical iPhone instead of the light frosted glass like Apple Music's tab bar. What I've confirmed: Same code works perfectly on iOS Simulator Apple Music and other Apple apps show correct Liquid Glass on same device Brand new Xcode project with just .glassEffect() also renders dark TestFlight build (App Store signing) has the SAME problem - still dark/gray This rules out developer signing vs App Store signing as the cause What I've tried: Clean build, delete derived data, reinstall app Completely reinstalled Xcode All accessibility settings correct (Reduce Transparency OFF, Liquid Glass set to Clear) Disabled Metal diagnostics Debug and Release builds Added window configuration for Extended sRGB/P3 color space Added AppDelegate with configureWindowForLiquidGlass() Tried .preferredColorScheme(nil) Tried background animation to force "live" rendering Environment: iPhone 17 Pro, iOS 26.3 Xcode 26.2 macOS 26.3 The question: Why does .glassEffect() work for Apple's apps but not third party apps, even with App Store signing via TestFlight? What am I missing?

Platform UIKit iOS UIActivityViewController Environment Device (issue reported): iPhone 16 iOS Version: 26.2 App Type: UIKit / Swift (standard modal presentation of UIActivityViewController) Summary When presenting UIActivityViewController to share a CSV file, the share sheet does not allow vertical scrolling, making lower actions (including Save to Files) unreachable. The same flow works correctly when sharing a PDF, and the issue cannot be reproduced on other test devices. Steps to Reproduce Launch the app and log in Navigate to More → Reports Tap Export Report Choose Export Report (CSV) Observe the share sheet Expected Result The user should be able to vertically scroll the share sheet All share actions (including Save to Files) should be reachable Actual Result Share sheet opens but vertical scrolling is disabled Lower options (including Save to Files) are not reachable No crash or console errors

Hello, I've a question about performance when trying to render lots of items coming from SwiftData via a @Query on a SwiftUI List. Here's my setup: // Item.swift: @Model final class Item: Identifiable { var timestamp: Date var isOptionA: Bool init() { self.timestamp = Date() self.isOptionA = Bool.random() } } // Menu.swift enum Menu: String, CaseIterable, Hashable, Identifiable { var id: String { rawValue } case optionA case optionB case all var predicate: Predicate<Item> { switch self { case .optionA: return #Predicate { $0.isOptionA } case .optionB: return #Predicate { !$0.isOptionA } case .all: return #Predicate { _ in true } } } } // SlowData.swift @main struct SlowDataApp: App { var sharedModelContainer: ModelContainer = { let schema = Schema([Item.self]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) return try! ModelContainer(for: schema, configurations: [modelConfiguration]) }() var body: some Scene { WindowGroup { ContentView() } .modelContainer(sharedModelContainer) } } // ContentView.swift struct ContentView: View { @Environment(\.modelContext) private var modelContext @State var selection: Menu? = .optionA var body: some View { NavigationSplitView { List(Menu.allCases, selection: $selection) { menu in Text(menu.rawValue).tag(menu) } } detail: { DemoListView(selectedMenu: $selection) }.onAppear { // Do this just once // (0..<15_000).forEach { index in // let item = Item() // modelContext.insert(item) // } } } } // DemoListView.swift struct DemoListView: View { @Binding var selectedMenu: Menu? @Query private var items: [Item] init(selectedMenu: Binding<Menu?>) { self._selectedMenu = selectedMenu self._items = Query(filter: selectedMenu.wrappedValue?.predicate, sort: \.timestamp) } var body: some View { // Option 1: touching `items` = slow! List(items) { item in Text(item.timestamp.description) } // Option 2: Not touching `items` = fast! // List { // Text("Not accessing `items` here") // } .navigationTitle(selectedMenu?.rawValue ?? "N/A") } } When I use Option 1 on DemoListView, there's a noticeable delay on the navigation. If I use Option 2, there's none. This happens both on Debug builds and Release builds, just FYI because on Xcode 16 Debug builds seem to be slower than expected: https://indieweb.social/@curtclifton/113273571392595819 I've profiled it and the SwiftData fetches seem blazing fast, the Hang occurs when accessing the items property from the List. Is there anything I'm overlooking or it's just as fast as it can be right now?

Fatal Exception: NSInternalInconsistencyException Cannot remove an observer <WKWebView 0x135137800> for the key path "configuration.enforcesChildRestrictions" from <STScreenTimeConfigurationObserver 0x13c6d7460>, most likely because the value for the key "configuration" has changed without an appropriate KVO notification being sent. Check the KVO-compliance of the STScreenTimeConfigurationObserver [class.] I noticed that on iOS 26, WKWebView registers STScreenTimeConfigurationObserver, Is this an iOS 26 system issue? What should I do?

When using UITraitBridgedEnvironmentKey to pass a trait value to the swift environment, it causes a crash when trying to access the value from the environment. The issue seems to be related to how swift uses the UITraitBridgedEnvironmentKey protocol since the crash occurs in swift::_getWitnessTable () from lazy protocol witness table accessor…. It can occur when calling any function that is generic using the UITraitBridgedEnvironmentKey type. I originally encountered the issue when trying to use a UITraitBridgedEnvironmentKey in SwiftUI, but have been able to reproduce the issue with any function with a similar signature. https://developer.apple.com/documentation/swiftui/environmentvalues/subscript(_:)-9zku Steps to Reproduce Requirements for the issue to occur Project with a minimum iOS version of iOS 16 Build the project with Xcode 26 Run on iOS 18 Add the following code to a project and call foo(key: MyCustomTraitKey.self) from anywhere. @available(iOS 17.0, *) func foo<K>(key: K.Type) where K: UITraitBridgedEnvironmentKey { // Crashes before this is called } @available(iOS 17.0, *) public enum MyCustomTraitKey: UITraitBridgedEnvironmentKey { public static let defaultValue: Bool = false public static func read(from traitCollection: UITraitCollection) -> Bool { false } public static func write(to mutableTraits: inout UIMutableTraits, value: Bool) {} } // The crash will occur when calling this. It can be added to a project anywhere // The sample project calls it from scene(_:willConnectTo:options:) foo(key: MyCustomTraitKey.self) For example, I added it to the SceneDelegate in a UIKit Project class SceneDelegate: UIResponder, UIWindowSceneDelegate { var window: UIWindow? func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) { if #available(iOS 17, *) { // The following line of code can be placed anywhere in a project, `SceneDelegate` is just a convenient place to put it to reproduce the issue. foo(key: MyCustomTraitKey.self) // ^ CRASH: Thread 1: EXC_BAD_ACCESS (code=1, address=0x10) } } } Actual Behaviour The app crashes with the stack trace showing the place calling foo but before foo is actually called. (ie, a breakpoint or print in foo is never hit) #0 0x000000019595fbc4 in swift::_getWitnessTable () #1 0x0000000104954128 in lazy protocol witness table accessor for type MyCustomTraitKey and conformance MyCustomTraitKey () #2 0x0000000104953bc4 in SceneDelegate.scene(_:willConnectTo:options:) at .../SceneDelegate.swift:20 The app does not crash when run on iOS 17, or 26 or when the minimum ios version is raised to iOS 17 or higher. It also doesn't crash on iOS 16 since it's not calling foo since UITraitBridgedEnvironmentKey was added in iOS 17. Expected behaviour The app should not crash. It should call foo on iOS 17, 18, and 26.

I’m trying to add a container view above a list view that stretches edge-to-edge across the device. What’s the recommended approach to achieve this layout with Swift UI? Example

Our project using UITabBarController and set a custom tabbar using below code: let customTabBar = CustomTabBar(with: dataSource) setValue(customTabBar, forKey: "tabBar") But when using Xcode 26 build app in iOS 26, the tabbar does not show: above code works well in iOS 18: below is the demo code: AppDelegate.swift: import UIKit @main class AppDelegate: UIResponder, UIApplicationDelegate { let window: UIWindow = UIWindow() func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { window.rootViewController = TabBarViewController() window.makeKeyAndVisible() return true } } CustomTabBar.swift: import UIKit class CustomTabBar: UITabBar { class TabBarModel { let title: String let icon: UIImage? init(title: String, icon: UIImage?) { self.title = title self.icon = icon } } class TabBarItemView: UIView { lazy var titleLabel: UILabel = { let titleLabel = UILabel() titleLabel.translatesAutoresizingMaskIntoConstraints = false titleLabel.font = .systemFont(ofSize: 14) titleLabel.textColor = .black titleLabel.textAlignment = .center return titleLabel }() lazy var iconView: UIImageView = { let iconView = UIImageView() iconView.translatesAutoresizingMaskIntoConstraints = false iconView.contentMode = .center return iconView }() private var model: TabBarModel init(model: TabBarModel) { self.model = model super.init(frame: .zero) setupSubViews() } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } private func setupSubViews() { addSubview(iconView) iconView.topAnchor.constraint(equalTo: topAnchor).isActive = true iconView.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true iconView.widthAnchor.constraint(equalToConstant: 34).isActive = true iconView.heightAnchor.constraint(equalToConstant: 34).isActive = true iconView.image = model.icon addSubview(titleLabel) titleLabel.topAnchor.constraint(equalTo: iconView.bottomAnchor).isActive = true titleLabel.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true titleLabel.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true titleLabel.heightAnchor.constraint(equalToConstant: 16).isActive = true titleLabel.text = model.title } } private var dataSource: [TabBarModel] init(with dataSource: [TabBarModel]) { self.dataSource = dataSource super.init(frame: .zero) setupTabBars() } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } override func sizeThatFits(_ size: CGSize) -> CGSize { var sizeThatFits = super.sizeThatFits(size) let safeAreaBottomHeight: CGFloat = safeAreaInsets.bottom sizeThatFits.height = 52 + safeAreaBottomHeight return sizeThatFits } private func setupTabBars() { backgroundColor = .orange let multiplier = 1.0 / Double(dataSource.count) var lastItemView: TabBarItemView? for model in dataSource { let tabBarItemView = TabBarItemView(model: model) addSubview(tabBarItemView) tabBarItemView.translatesAutoresizingMaskIntoConstraints = false tabBarItemView.topAnchor.constraint(equalTo: topAnchor).isActive = true tabBarItemView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true if let lastItemView = lastItemView { tabBarItemView.leadingAnchor.constraint(equalTo: lastItemView.trailingAnchor).isActive = true } else { tabBarItemView.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true } tabBarItemView.widthAnchor.constraint(equalTo: widthAnchor, multiplier: multiplier).isActive = true lastItemView = tabBarItemView } } } TabBarViewController.swift: import UIKit class NavigationController: UINavigationController { override func viewDidLoad() { super.viewDidLoad() } } class HomeViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .red navigationItem.title = "Home" } } class PhoneViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .purple navigationItem.title = "Phone" } } class PhotoViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .yellow navigationItem.title = "Photo" } } class SettingViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .green navigationItem.title = "Setting" } } class TabBarViewController: UITabBarController { override func viewDidLoad() { super.viewDidLoad() let homeVC = HomeViewController() let homeNav = NavigationController(rootViewController: homeVC) let phoneVC = PhoneViewController() let phoneNav = NavigationController(rootViewController: phoneVC) let photoVC = PhotoViewController() let photoNav = NavigationController(rootViewController: photoVC) let settingVC = SettingViewController() let settingNav = NavigationController(rootViewController: settingVC) viewControllers = [homeNav, phoneNav, photoNav, settingNav] let dataSource = [ CustomTabBar.TabBarModel(title: "Home", icon: UIImage(systemName: "house")), CustomTabBar.TabBarModel(title: "Phone", icon: UIImage(systemName: "phone")), CustomTabBar.TabBarModel(title: "Photo", icon: UIImage(systemName: "photo")), CustomTabBar.TabBarModel(title: "Setting", icon: UIImage(systemName: "gear")) ] let customTabBar = CustomTabBar(with: dataSource) setValue(customTabBar, forKey: "tabBar") } } And I have post a feedback in Feedback Assistant(id: FB18141909), the demo project code can be found there. How are we going to solve this problem? Thank you.