title: AvalonDock : When using DocumentPane binding, the tabs for new DocumentContent items aren't clickable
body: <p>I'm trying to bind a DocumentPane to the property ObservableCollection&lt;DocumentContent&gt; DocumentContent, using the xaml below.</p>
  
  <pre><code>&lt;ad:DocumentPane Name="documentPane" ShowHeader="True" ItemsSource="{Binding Path=DocumentContent, Mode=OneWay}"&gt;&lt;/ad:DocumentPane&gt;
  </code></pre>
  
  <p>My problem is that when a new DocumentContent object is added to the ObservableCollection, it adds the tab to the DocumentPane correctly, but the tab is not clickable.</p>
  
  <p>Before I switched to data binding I was using document.Items.Add( new DocumentContent() ), which worked as expected.</p>
  
  <p>Does anyone have any ideas why the tabs would not be clickable if they're added via data binding?</p>