touch bar NSSliderTouchBarItem problem

touchbar.swift

import Cocoa

extension NSTouchBarItem.Identifier {
    static let sliderTest = NSTouchBarItem.Identifier("test.bar.slider")
}

extension NSTouchBar.CustomizationIdentifier {
    static let testBar = NSTouchBar.CustomizationIdentifier("test.bar")
}

class App: NSApplication, NSApplicationDelegate, NSTouchBarDelegate {

    func applicationDidFinishLaunching(_ notification: Notification) {
        NSApp.setActivationPolicy(.regular)
        atexit_b { NSApp.setActivationPolicy(.prohibited) }

        NSApp.activate(ignoringOtherApps: true)
    }

    override func makeTouchBar() -> NSTouchBar? {
        let touchBar = NSTouchBar()
        touchBar.delegate = self
        touchBar.customizationIdentifier = .testBar
        touchBar.defaultItemIdentifiers = [.sliderTest]
        touchBar.customizationAllowedItemIdentifiers = [.sliderTest]
        return touchBar
    }

    func touchBar(_ touchBar: NSTouchBar, makeItemForIdentifier identifier: NSTouchBarItem.Identifier) -> NSTouchBarItem? {
        switch identifier {
        case NSTouchBarItem.Identifier.sliderTest:
            let tbItem = NSSliderTouchBarItem(identifier: identifier)
            tbItem.customizationLabel = "test";
            return tbItem;
        default:
            return nil
        }
    }

}

let app = App.shared
NSApp = app
app.delegate = app as? NSApplicationDelegate
app.run()