title: DataTemplate does not show up with TabControl
body: <p>i am using a DataBinding to show all Controls in the ItemsSource</p>
  
  <pre><code>        &lt;TabControl Grid.Row="1" TabStripPlacement="Left" ItemsSource="{Binding Source={StaticResource WorkflowSelector}, Path=Workflows}" SelectedIndex="0"&gt;
          &lt;TabControl.ItemTemplate&gt;
              &lt;DataTemplate&gt;
                  &lt;Label Content="{Binding PluginName}"&gt;&lt;/Label&gt;
              &lt;/DataTemplate&gt;
          &lt;/TabControl.ItemTemplate&gt;
      &lt;/TabControl&gt;
  </code></pre>
  
  <p>the WorkflowSelector is my ViewModel which contains a List of all Controls that should be shown in the TabControl.</p>
  
  <p>I created an itemTemplate to show the PluginName (public property) in the Tab
  but nothing is shown.</p>
  
  <p>If i inspect the Visual tree i can see the Databinding of the Tabcontrol, containing 1 Item that has a Property PluginName.
  The evaluated Value of the BindingExpression of the Label is empty </p>
  
  <p>first thing i noticed is that the ContentPresenter does not have a DataContext, while the Border does have the correct DataContext</p>
  
  <p><a href="https://i.stack.imgur.com/J385o.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/J385o.png" alt="Visual Tree of the application; ContentPresenter does not hold the DataContext "></a></p>
  
  <p>Additionally ... if i change the ItemTemplate to ContentTemplate the binding is working correctly (but in the content not in the header)</p>