embedding a xamarin forms content page

Description

The layout of an Embedded Xamarin.Forms ContentPage doesn't refres when the Windows size changes.

Steps to Reproduce

1. Create any Xamarin.Forms Page (example used below)

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="htp://xamarin.com/schemas/2014/forms"
             xmlns:x="htp://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="NavigationPannel2.PageTest1"
            xmlns:local="clr-namespace:NavigationPannel2"
             BackgroundColor="Aqua">
    <ContentPage.Content>
        <Grid>
            <Button Text="To Page 2"
                    Clicked="Button_Clicked"/>
        </Grid>
    </ContentPage.Content>
</ContentPage>

initialize Forms.Init() in OnLaunched :

(sample code below)

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

namespace NavigationPannel2.UWP
{
    /// <summary>
    /// Provides application-specific behavior to supplement the default Application class.
    /// </summary>
    sealed partial class App : Application
    {
        /// <summary>
        /// Initializes the singleton application object.  This is the first line of authored code
        /// executed, and as such is the logical equivalent of main() or WinMain().
        /// </summary>
        public App()
        {
            this.InitializeComponent();
            this.Suspending += OnSuspending;
        }

        /// <summary>
        /// Invoked when the application is launched normally by the end user.  Other entry points
        /// will be used such as when the application is launched to open a specific file.
        /// </summary>
        /// <param name="e">Details about the launch request and process.</param>
        protected override void OnLaunched(LaunchActivatedEventArgs e)
        {

            Xamarin.Forms.Forms.Init(e);
            Frame rootFrame = Window.Current.Content as Frame;

            // Do not repeat app initialization when the Window already has content,
            // just ensure that the window is active
            if (rootFrame == null)
            {
                // Create a Frame to act as the navigation context and navigate to the first page
                rootFrame = new Frame();

                rootFrame.NavigationFailed += OnNavigationFailed;

                Xamarin.Forms.Forms.Init(e);

                if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
                {
                    //TODO: Load state from previously suspended application
                }

                // Place the frame in the current Window
                Window.Current.Content = rootFrame;
            }

            if (rootFrame.Content == null)
            {
                // When the navigation stack isn't restored navigate to the first page,
                // configuring the new page by passing required information as a navigation
                // parameter
                rootFrame.Navigate(typeof(MainPage), e.Arguments);
            }
            // Ensure the current window is active
            Window.Current.Activate();
        }

        /// <summary>
        /// Invoked when Navigation to a certain page fails
        /// </summary>
        /// <param name="sender">The Frame which failed navigation</param>
        /// <param name="e">Details about the navigation failure</param>
        void OnNavigationFailed(object sender, NavigationFailedEventArgs e)
        {
            throw new Exception("Failed to load Page " + e.SourcePageType.FullName);
        }

        /// <summary>
        /// Invoked when application execution is being suspended.  Application state is saved
        /// without knowing whether the application will be terminated or resumed with the contents
        /// of memory still intact.
        /// </summary>
        /// <param name="sender">The source of the suspend request.</param>
        /// <param name="e">Details about the suspend request.</param>
        private void OnSuspending(object sender, SuspendingEventArgs e)
        {
            var deferral = e.SuspendingOperation.GetDeferral();
            //TODO: Save application state and stop any background activity
            deferral.Complete();
        }
    }
}

3. use this page as content for aUWP MainPage :

using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using Xamarin.Forms;

using Xamarin.Forms;
using Xamarin.Forms.Platform.UWP;

using Windows.UI.Core;
namespace NavigationPannel2.UWP
{
    public sealed partial class MainPage
    {
        public MainPage()
        {
            this.InitializeComponent();

            LoadApplication(new NavigationPannel2.App());
            CustomContentPage page = new PageTest1();
            Content = page.CreateFrameworkElement();

        }
    }
}

Expected Behavior

the Xamarin.forms ContentPage acts as a uwp page.

Actual Behavior

the Xamarin.Forms Layout doesn't refresh when the Windows changes size.