Opening an NSViewController as a Sheet

I have a SwiftUI view with a button. I want to open a window sheet from a storyboard. Showing a window sheet isn't a problem. It's just that the application no longer has a menu bar. As soon as I created a storyboard and a view controller (NSViewController), the application stopped showing up properly. Now, if I try to debug it (Command + R), the window won't appear. So I have to click on the Live Preview button on the Canvas. If I do, I can click on the Bring Forward button. Finally, if I click on it, the application window always appears at the bottom-left corner of the desktop without the menu bar. So what's the issue?

Anyway, the following is my code.

Code Block 
// SwiftUI View //
import SwiftUI
struct ContentView: View {
    @State private var sheetPresented = false
    @State private var selectionIndex = 3
    
    var body: some View {
        ZStack {
            VStack {
                Button(action: {
                    sheetPresented = true
                }) {
                    Text("Show me a sheet")
                }
                .sheet(isPresented: $sheetPresented) {
                    SheetViewControllerRepresentation(message: String(selectionIndex))
                }
            }
        }.frame(minWidth: 360, idealWidth: 360, maxWidth: 360, minHeight: 240, idealHeight: 240, maxHeight: 240, alignment: .center)
    }
}
// View controller //
import Cocoa
import SwiftUI
class SheetViewController: NSViewController {
    // MARK: -
    var message = String()
    
    
    // MARK: - IBOutlet
    @IBOutlet weak var messageLabel: NSTextField!
    
    
    // MARK: - Life cycle
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do view setup here.
    }
    
    override func viewWillAppear() {
        super.viewWillAppear()
        
        messageLabel.stringValue = message
    }
    
    override func viewDidAppear() {
        super.viewDidAppear()
        
        view.setFrameSize(CGSize(width: 320, height: 220))
    }
}
struct SheetViewControllerRepresentation: NSViewControllerRepresentable {
    var message = String()
    
    func makeNSViewController(context: NSViewControllerRepresentableContext<SheetViewControllerRepresentation>) -> SheetViewController {
        let mainStoryboard = NSStoryboard(name: "Main", bundle: nil)
        let sheetViewController = mainStoryboard.instantiateController(withIdentifier: "SheetView") as! SheetViewController
        sheetViewController.message = self.message
        return sheetViewController
    }
    
    func updateNSViewController(_ nsViewController: SheetViewController, context: NSViewControllerRepresentableContext<SheetViewControllerRepresentation>) {
    }
}

Thank you.