How can I wait for child controls to exist when programmatically switching tabs?

I am building a wizard-like detail view popup for handling a multi-step workflow. I have created the necessary layout in Model.xafml, and am able to display and click between tabs. But I want to add Next/Previous buttons to the view, and programmatically switch between tabs. The issue I am having is that I need to interact with a child listview on the newly active tab. But the list view doesn't exist yet.

I've tried using a ManualResetEvent, to wait for the child view to get created. But then it blocks and the view doesn't get created. So I need to create some sort of callback or event that I can trigger when on the new tab, and the controls are created.

I'm at a bit of a loss how to set this up, and even how to describe what I need to do. How do I wait for the new tab to finish loading?

    public void Next_Clicked() {        var index = ++tabModel.ActiveTabIndex;        if (index == 1)        {            var retries = 0;            // NOTE: attempted to wait for PoliciesFrame to exist            while (!PoliciesListViewCreated.WaitOne(1000) && retries++< 5)            {            }            // NOTE: this line fails because PoliciesFrame is null              var linkUnlinkController = PoliciesFrame.GetController<LinkUnlinkController>();            var window = Frame.GetController<WindowController>().Window;            // display the link popup automatically.            linkUnlinkController.LinkAction.DoExecute(window);        }    }    protected override void CustomizeWindowPopup(object sender,     CustomizePopupWindowParamsEventArgs e)    {        base.CustomizeWindowPopup(sender, e);        DetailView.CustomizeViewItemControl<ListPropertyEditor>(this,             ChildPropertyEditor, nameof(Transaction.Policies));    }    private void ChildPropertyEditor(ListPropertyEditor listPropertyEditor)    {        PoliciesListView = listPropertyEditor.ListView;        PoliciesFrame = listPropertyEditor.Frame;        PoliciesListView.SelectionChanged += NestedListView_SelectionChanged;        // NOTE: this is not working. How to notify when ready?        PoliciesListViewCreated.Set();    }