<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Style TargetType="{x:Type ExtendedListBox}" BasedOn="{StaticResource {x:Type ListBox}}">
        <Setter Property="Background" Value="{DynamicResource ControlBackgroundBrush}" />
    </Style>
</ResourceDictionary>