Tabbed Windows on UIKitForMac

Does anyone know how to implement the multiple tab kind of behaviour on a UIKitForMac app ( to have multiple instances of the app, tabbed, as you have in safari )
On a UIKitForMac app, I opened 2 instance of the same app and I was able to drag one instance to the tab bar of the other one and then to have the same tabbed behaviour as the one from safari .