PageViewContainer prevents App.MainPage change from working

[therealjohn]

I've run into a scenario where a Page with a PageViewContainer and a button that calls App.Current.MainPage = new NavigationPage(new MyPage()) does not work. The app appears to not change the MainPage.

However, MainPage is set, and if you minimize the application on iOS, then open it back up it will be correct.

Consider this page:

<ContentPage 
    xmlns="http://xamarin.com/schemas/2014/forms" 
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
    xmlns:ttc="clr-namespace:TwinTechs.Controls;assembly=TwinTechsForms"
    x:Class="CaseProjectTest.Views.MyPage" 
    Title="My Page">
    <ContentPage.Content>


        <StackLayout>

        <ttc:PageViewContainer>
            VerticalOptions="FillAndExpand"
            HorizontalOptions="FillAndExpand">

            <ttc:PageViewContainer.Content>

                <ContentPage>
                    <Label Text="Page in a Page"></Label>
                </ContentPage>

            </ttc:PageViewContainer.Content>

        </ttc:PageViewContainer>

        <Button Text="Click Me" Command="{Binding NavigateCommand}"/>

    </StackLayout>

    </ContentPage.Content>
</ContentPage>

The button command will cause App.Current.MainPage = new NavigationPage(new MyPageTwo()); to happen. MyPageTwo is just an empty ContentPage. When you press the button, MyPage is still showing. I would expect MyPageTwo to show (within the NavigationPage).