<UserControl x:Class="UserControlBindingTest.UserControl2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="300" Width="300"
    x:Name="_userControl">
    
    <StackPanel>

        <ListBox ItemsSource="{Binding ElementName=_userControl, Path=Tests2}">
        </ListBox>

        <ListBox ItemsSource="{Binding Items}">
        
        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Name}"></TextBlock>
            </DataTemplate>
        </ListBox.ItemTemplate>
        
    </ListBox>
        
    </StackPanel>
</UserControl>

<UserControl x:Class="UserControlBindingTest.UserControl2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="300" Width="300"
    x:Name="_userControl">
    
    <StackPanel>

        <ListBox ItemsSource="{Binding ElementName=_userControl, Path=Tests2}">
        </ListBox>

        <ListBox ItemsSource="{Binding Items}">
        
        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Name}"></TextBlock>
            </DataTemplate>
        </ListBox.ItemTemplate>
        
    </ListBox>
        
    </StackPanel>
</UserControl>