title: Why does StringFormat have no effect on the binding of my MenuItem.Header?
body: <p>All of my 6 samples have "StringFormat" in their binding but none is applied and I'm only getting the value without any formatting.</p>
  
  <p>Any idea what I do wrong?</p>
  
  <pre><code>&lt;MenuItem Header="{Binding SeriesNearMouse.Count, StringFormat='Series {0}'}"&gt;
  &lt;/MenuItem&gt;
  
  &lt;MenuItem DataContext="SeriesNearMouse"&gt;
      &lt;MenuItem.Header&gt;
          &lt;Binding Path="Count" 
                      StringFormat="Series{0:D}test"&gt;
          &lt;/Binding&gt;
      &lt;/MenuItem.Header&gt;
  
  &lt;/MenuItem&gt;
  &lt;MenuItem&gt;
      &lt;MenuItem.Header&gt;
          &lt;Binding Path="SeriesNearMouse.Count" 
                      StringFormat="Series{0}"&gt;
          &lt;/Binding&gt;
      &lt;/MenuItem.Header&gt;
  &lt;/MenuItem&gt;
  
  &lt;MenuItem Header="{Binding SeriesNearMouse.Count, StringFormat='{}Series {0}'}"&gt;
  &lt;/MenuItem&gt;
  
  &lt;MenuItem DataContext="SeriesNearMouse"&gt;
      &lt;MenuItem.Header&gt;
          &lt;Binding Path="Count" 
                      StringFormat="{}Series{0:D}test"&gt;
          &lt;/Binding&gt;
      &lt;/MenuItem.Header&gt;
  
  &lt;/MenuItem&gt;
  &lt;MenuItem&gt;
      &lt;MenuItem.Header&gt;
          &lt;Binding Path="SeriesNearMouse.Count" 
                      StringFormat="{}Series{0}"&gt;
          &lt;/Binding&gt;
      &lt;/MenuItem.Header&gt;
  &lt;/MenuItem&gt;
  </code></pre>