How do I create a tabbed panel similar to the Xcode properties panel

Question

I am trying to create a tabbed panel similar to the Xcode properties panel but the standard tabbed panel appears to have a different look and feel with no way to change it. What controls should be used to create a similar looking tabbed panel?

EDIT: I was not using a NSTabViewController - just had the TabView !!

Answer 1

I just created a new project with storyboard and with the provided layout, added to the View Controllers view a custom view at top. To the custom view added buttons, style = square, type = toggle, and used provided icons of type template. Assigned tag to buttons 0-4 and did put them to a horizontal stack view. Then added a horizontal line and a container view. Then I add a Tab View Controller to the storyboard and embed it to container view. All buttons are connected to same action.

import Cocoa

class ViewController: NSViewController {

    @IBOutlet var myStackView: NSStackView!

    var oldSelection: Int = 0
    var newSelection: Int = 0

    var buttons: [NSButton]?
    var tabViewDelegate: NSTabViewController?

    @IBAction func selectedButton(_ sender: NSButton) {
        newSelection = sender.tag
        tabViewDelegate?.selectedTabViewItemIndex = newSelection

        buttons![oldSelection].state = .off
        sender.state = .on

        oldSelection = newSelection
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        buttons = (myStackView.arrangedSubviews as! [NSButton])
    }

    override var representedObject: Any? {
        didSet {
        // Update the view, if already loaded.
        }
    }

    override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
        // Once on load
        tabViewDelegate = segue.destinationController as?  NSTabViewController
    }

}