Flyout Disappears on Window Resize: What Could Be Wrong?

    public partial class AppShell : Shell
    {
        public AppShell()
        {
            InitializeComponent();

        }
        private void OnToggleClicked(object sender, EventArgs e)
        {
            if (Shell.Current.FlyoutBehavior == FlyoutBehavior.Locked)
            {
                Shell.Current.FlyoutIsPresented = !Shell.Current.FlyoutIsPresented;
            }
        }
    }