title: How to set the background of All ListBox items when ListBox is focused
body: <p>I just can't seem to figure this out!<br>
  I want to change the background of ALL items to Yellow when the <code>ListBox</code> has focus.<br>
  What am I doing wrong?</p>
  
  <pre><code>&lt;ListBox x:Name="ManufacturerList" Grid.Row="10" Foreground="Black" FontSize="16" Background="DarkGray" HorizontalContentAlignment="Stretch"
           ItemsSource="{Binding Manufacturers}"&gt;
      &lt;ListBox.ItemContainerStyle&gt;
          &lt;Style TargetType="ListBoxItem"&gt;
              &lt;Setter Property="Background" Value="White" /&gt;
              &lt;Style.Triggers&gt;
                  &lt;DataTrigger Binding="{Binding ElementName=ManufacturerList, Path=IsFocused}" Value="True"&gt;
                      &lt;Setter Property="Background" Value="Yellow" /&gt;
                  &lt;/DataTrigger&gt;
              &lt;/Style.Triggers&gt;
          &lt;/Style&gt;
      &lt;/ListBox.ItemContainerStyle&gt;
  &lt;/ListBox&gt;
  </code></pre>