title: Set Style for all elements inside ContentPresenter
body: <p>I overrided the template of wpf expander. 
  The header has ContentPresenter</p>
  
  <pre><code>&lt;ContentPresenter x:Name="HeaderContent"
                    Grid.Column="1"
                    Margin="0,0,4,0"
                    HorizontalAlignment="Left"
                    VerticalAlignment="Center"
                    RecognizesAccessKey="True"
                    SnapsToDevicePixels="True"
                    &gt;
      &lt;ContentPresenter.Resources&gt;
          &lt;Style BasedOn="{StaticResource Expanderheader-Naming}" 
                 TargetType="{x:Type TextBlock}" /&gt;
       &lt;/ContentPresenter.Resources&gt;
  &lt;/ContentPresenter&gt;
  </code></pre>
  
  <p>Where I tried to add my style for all TextBlocks inside.
  My style works if I set the header as a property:</p>
  
  <pre><code>&lt;Expander Header="HelloWorld"&gt;
  </code></pre>
  
  <p>But it doesn't when I try to set it in the other manner.</p>
  
  <pre><code>&lt;Expander&gt;
      &lt;Expander.Header&gt;
          &lt;Grid x:Name="MyGrid"&gt;
              &lt;TextBlock&gt;Hello Man&lt;/TextBlock&gt;
          &lt;/Grid&gt;  
      &lt;/Expander.Header&gt;
  &lt;/Expander&gt;
  </code></pre>
  
  <p>How to set this style for any TextBlocks inside the ContentPresenter?</p>