macOS menubar application: main menu not being displayed

This is my workaround solution for now:

As I wrote in the question, if I click on another app and come back to my app, the menubar is being displayed. I am simulating this when I try to show the preference window:

    NSApp.setActivationPolicy(.regular)
    NSApp.activate(ignoringOtherApps: true)
    window.makeKeyAndOrderFront(nil)

   if (NSRunningApplication.runningApplications(withBundleIdentifier: "com.apple.dock").first?.activate(options: []))! {
       let deadlineTime = DispatchTime.now() + .milliseconds(200)
       DispatchQueue.main.asyncAfter(deadline: deadlineTime) {                 
       NSApp.setActivationPolicy(.regular)
            NSApp.activate(ignoringOtherApps: true)
       }
   }

This is not a perfect solution. If I don't find a better solution, I will file a bug.

Based on the fix (or workaround) from OP. The key is really to toggle out and back to focus (thanks @Daniel!).

Some small improvements:

No force unwrapping, no need to set ActivationPolicy and call activate twice.

NSApp.setActivationPolicy(.regular)
window.makeKeyAndOrderFront(nil)    

NSRunningApplication.runningApplications(withBundleIdentifier: "com.apple.dock").first?.activate(options: [])

OperationQueue.current?.underlyingQueue?.asyncAfter(deadline: .now() + .milliseconds(200), execute: {
    NSApp.activate(ignoringOtherApps: true)
})