How to handle enabled property of multiple tabs using Data Templates?

I have a Window with two tabs, that holds two different user controls. In order to enable/disable navigation to the second tab, I implement an IsEnabled property in both VM's from the IPageViewModel interface.

The IsEnabled boolean property is set to true when a SelectedCustomer is received in the CustomerOrdersViewModel, via Messenger service from CustomerDetailsViewModel.

So far this method works, as the second tab is enabled when I select a customer from the data grid in the first view. But the problem is when I try to select the first tab to go back to the initial view, it is disabled.

This is a screen cast of the specific navigation issue.

I'm not sure why as I thought when I set the IsEnabled property to true using the messenger, both tabs would be enabled.

Does anyone have any advice on the issue here?

In the CustomerDetailsViewModel I send the selectedCustomer via a messenger:

    private CustomerModel selectedCustomer;
    public CustomerModel SelectedCustomer
    {
        get
        {
            return selectedCustomer;
        }
        set
        {
            selectedCustomer = value;
            Messenger.Default.Send<CustomerModel>(selectedCustomer);
            RaisePropertyChanged("SelectedCustomer");
        }
    }

Then in the CustomerDetailsViewModel the IsEnabled property is set to true as the SelectedCustomer has been passed over:

    public CustomerOrdersViewModel()
    {


        Messenger.Default.Register<CustomerModel>(this, OnCustomerReceived);


    }


    public void OnCustomerReceived(CustomerModel customer)
    {
        SelectedCustomer = customer;
        IsEnabled = true;
    }

This is the ApplicationView xaml that holds both user controls, and the tabs generated for each:

<Window x:Class="MongoDBApp.Views.ApplicationView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:views="clr-namespace:MongoDBApp.Views"
        xmlns:vm="clr-namespace:MongoDBApp.ViewModels"
        Title="ApplicationView"
        Width="800"
        Height="500">

    <Window.Resources>
        <DataTemplate DataType="{x:Type vm:CustomerDetailsViewModel}">
            <views:CustomerDetailsView />
        </DataTemplate>
        <DataTemplate DataType="{x:Type vm:CustomerOrdersViewModel}">
            <views:CustomerOrdersView />
        </DataTemplate>
    </Window.Resources>

    <Window.DataContext>
        <vm:ApplicationViewModel />
    </Window.DataContext>


    <TabControl ItemsSource="{Binding PageViewModels}"
                SelectedItem="{Binding CurrentPageViewModel}"
                TabStripPlacement="Top">
        <TabControl.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Name}" />
            </DataTemplate>
        </TabControl.ItemTemplate>
        <TabControl.ItemContainerStyle>
            <Style TargetType="{x:Type TabItem}">
                <Setter Property="IsEnabled" Value="{Binding IsEnabled}"/>
            </Style>
        </TabControl.ItemContainerStyle>
    </TabControl>
</Window>

Why not just default the IsEnabled property of the CustomerDetailsViewModel to true?

It's a tab that should always be enabled, so that would make the most sense to me.