title: Why is binding to "Self" not working?
body: <p>I try to bind the control's <code>Tag</code> property to the control's <code>Visibility</code> property, but I receive the following error in VS:</p>
  
  <blockquote>
    <p>object reference not set to an instance of an object</p>
  </blockquote>
  
  <p>The XAML is like below:</p>
  
  <pre><code>&lt;RadioButton GroupName="NavButtonSide" 
               Tag="7"  
               Visibility="{Binding Path=Tag, 
                                    Converter={StaticResource ControlTagVisibilityConverter}, 
                                    RelativeSource={RelativeSource Mode=Self}}"/&gt;
  </code></pre>
  
  <p>Can anyone tell me how to solve it?</p>