Started to learn Swift and got stuck...

Hello

I started learning Swift through "Develop in Swift Fundamentals" version for Xcode 12 by Apple Books. Everything more or less went smoothly for first few chapters until I got stuck on Guided Project: Light. It's the part talking about using Refactor > Extract to Method. No matter what I try, Extract to Method is greyed out in the Editor menu, or, if I try with right click on selected code it just making clicking notification sound... If I run app in simulator it works fine, but my understanding is that Refactor is important part of Swift, so I guess it would be nice if it would work.

I'm using Xcode 12.5.1 on Big Sur 11.5.1

I also tried uninstall / install Xcode, and even tried with the latest beta and nothing different.

Code I have is the following:

import UIKit

class ViewController: UIViewController {

@IBOutlet var lightButton: UIButton!
var lightOn = true

override func viewDidLoad() {
    super.viewDidLoad()
}

@IBAction func buttonPressed(_ sender: Any) {
   
    lightOn.toggle()
    if lightOn {
        view.backgroundColor = .white
    }
    else
    {
        view.backgroundColor = .black
    }
}

}

Instructions are to highlight:

lightOn.toggle() if lightOn { view.backgroundColor = .white } else { view.backgroundColor = .black }

And use Refactor > Extract to Method from the Editor menu. That is greyed out. I tried to select more code, but same result...

Any help would be greatly appreciated.