Prefered Style Container for the Components in the DataTemplate
You can merge the two style in the DataTemplate.Resources so that it can be applied in all the Borders inside the DataTemplate. Refer the below code.

&lt;DataTemplate DataType="{x:Type m:myFoo}"&gt;
        &lt;DataTemplate.Resources&gt;
            &lt;!-- 1) Style Applied to the Border --&gt;
            &lt;Style TargetType="Border"&gt;
                &lt;Setter Property="Margin" Value="1"/&gt;
                &lt;Style.Triggers&gt;
                    &lt;DataTrigger Binding="{Binding Path=Active}"&gt;
                        &lt;Setter Property="Background" Value="OrangeRed"/&gt;
                    &lt;/DataTrigger&gt;
                &lt;/Style.Triggers&gt;
            &lt;/Style&gt;
        &lt;/DataTemplate.Resources&gt;
        &lt;Border&gt;
            &lt;Grid&gt;
                &lt;Border&gt;
                    &lt;!-- Guts --&gt;
                 &lt;/Border&gt;
            &lt;/Grid&gt;                
        &lt;/Border&gt;
    &lt;/DataTemplate&gt;