public void RegisterPopUp_PopUpToRegIsAncestorOfActive_DoesNotCallActivePopUp()
    {
        IUIElement       rootUIE      = Substitute.For <IUIElement>();
        TestPopUpManager popUpManager = new TestPopUpManager();

        popUpManager.SetRootUIElement(rootUIE);
        IPopUp popUpToRegister = Substitute.For <IPopUp>();
        IPopUp activePopUp     = Substitute.For <IPopUp>();

        popUpToRegister.IsAncestorOf(activePopUp).Returns(true);
        popUpManager.SetActivePopUp_Test(activePopUp);

        popUpManager.RegisterPopUp(popUpToRegister);

        rootUIE.DidNotReceive().PopUpDisableRecursivelyDownTo(popUpToRegister);
        activePopUp.DidNotReceive().PopUpDisableRecursivelyDownTo(popUpToRegister);
    }