UITabbarItem似乎忽略了瑞典语字符

Question

我有一个从UITabBarController子类化的简单视图控制器。在将项目分配给标签栏控制器时，我遇到了UITabBarItem

标题的一些问题

class LandingVC: UITabBarController, UITabBarControllerDelegate {

override func viewDidLoad() {
    super.viewDidLoad()

    let storyboard = UIStoryboard(name: "Ssettings", bundle: nil)
    let vc1 = storyboard.instantiateViewController(withIdentifier: "bookID")
    let tab1 = UITabBarItem(title: "Föo", image: nil, selectedImage: nil)
    vc1.tabBarItem = tab1

    let vc2 = storyboard.instantiateViewController(withIdentifier: "SettingsID")
    let tab2 = UITabBarItem(title: "Sök", image: nil, selectedImage: nil)
    vc2.tabBarItem = tab2

    self.viewControllers = [vc1, vc2]
    }
}

但是奇怪的是，标签栏控制器显示标题为Sok和Foo的项目而忽略了瑞典语字符。甚至选项卡的systemItem似乎也失败了，我们将不胜感激