title: ContentControl not showing Content
body: <p>I have a custom <code>ContentControl</code> which has a fixed XAML layout like a <code>UserControl</code> (Rather than the usual applied generic template).</p>
  
  <p>Previously this layout had no extra markup, so it was literally:</p>
  
  <pre><code>&lt;ContentControl x:Class="MyControls.CustomViewControl"
               xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
               xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
               xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
               xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
               mc:Ignorable="d" 
               d:DesignHeight="300" d:DesignWidth="300"&gt;
  &lt;/ContentControl&gt;
  </code></pre>
  
  <p>This worked fine.</p>
  
  <p>I now want to put a border around the content, so I have changed the XAML to:</p>
  
  <pre><code>&lt;ContentControl x:Class="MyControls.CustomViewControl"
               xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
               xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
               xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
               xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
               mc:Ignorable="d" 
               d:DesignHeight="300" d:DesignWidth="300"&gt;
      &lt;ContentControl.Template&gt;
          &lt;ControlTemplate&gt;
              &lt;Border BorderThickness="5" BorderBrush="LightGreen"&gt;
                  &lt;ContentPresenter /&gt;
              &lt;/Border&gt;
          &lt;/ControlTemplate&gt;
      &lt;/ContentControl.Template&gt;
  &lt;/ContentControl&gt;
  </code></pre>
  
  <p>This shows the border, but no content.</p>
  
  <p>I tried supplying an explicit binding for ContentPresenter:</p>
  
  <pre><code>&lt;ContentPresenter Content="{Binding Path=Content, RelativeSource={RelativeSource Self}}"/&gt;
  </code></pre>
  
  <p>But this made no difference.</p>
  
  <p>Setting an explicit <code>Content</code> does work:</p>
  
  <pre><code>&lt;ContentPresenter Content="TEST" /&gt;
  </code></pre>
  
  <p>Anyone know why the Content binding doesn't work? I guess I could fall back to the usual generic template but it would be easier if I could just do it directly like a UserControl.</p>