How to add Tabs in a non-document-based app under macOS?

Question

I like to build an app in Swift 3 with Xcode 8 and it should enable the Apple tab bar. It is not document-based. I learned here, that the tabs can be enabled if I override t

Answer 1

In case above "+" will add new tab always after first window, if you close first window then it will be recreated under current window.

there is way to get it work

override func newWindowForTab(_ sender: Any?) {
    let wc: NSWindowController = self.storyboard?.instantiateInitialController() as! NSWindowController
    wc.window?.windowController = self
    NSApplication.shared.mainWindow!.addTabbedWindow(wc.window!, ordered: .above)
    wc.window?.orderFront(self)
}

trick in NSApplication.shared.mainWindow! you always add tab to current active window.

and if we need create window at the end we should use this trick

let tabbedWindows = NSApplication.shared.mainWindow!.tabbedWindows!
let lastTabIdx = tabbedWindows.count - 1
tabbedWindows[lastTabIdx].addTabbedWindow(wc.window!, ordered: .above)