Just upgraded Forms to 4.0.0.394984-pre10 and I get "Active Shell Item not set"

Hi,

I don't know where the error occurs. The log shows this:

D/Mono (24329): Assembly Ref addref Xamarin.Android.Support.Fragment[0xe19321c0] -> Xamarin.Android.Arch.Lifecycle.LiveData.Core[0xe1931440]: 2
D/Mono (24329): Assembly Ref addref Xamarin.Android.Support.Design[0xe1931f80] -> Xamarin.Android.Support.CustomView[0xe1931ec0]: 3
Unhandled Exception:

System.ArgumentException: Active Shell Item not set. Have you added any Shell Items to your Shell?
Parameter name: ShellItem

This is my shell :

<Shell  x:Name="appShell"
        x:Class="C2Mobile.Features.Shell.AppShell"
        xmlns="http://xamarin.com/schemas/2014/forms"
        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
        xmlns:local="clr-namespace:C2Mobile.Features.Shell">

 <ShellItem Route="tabs" Title="Home" FlyoutIcon="ia">
        <ShellSection Title="Logout" Icon="ia" Route="login">
            <ShellContent ContentTemplate="{DataTemplate login:LogInPage}" Route="logout"/>
        </ShellSection>
    </ShellItem>

    <MenuItem
        BindingContext="{x:Reference appShell}"
        Command="{Binding BindingContext.LogOutCommand}"
        Text="Log out" />
</Shell>

Thanks,

Francis