title: Converters on child bindings in a MultiBinding
body: <p>Suppose I have this MultiBinding:</p>
  
  <pre><code>&lt;MultiBinding Converter="{StaticResource FooBarConverter}&gt;
    &lt;Binding Path="Foo" Converter="{StaticResource FooConverter}" /&gt;
    &lt;Binding Path="Bar" Converter="{StaticResource BarConverter}" /&gt;
  &lt;/MultiBinding&gt;
  </code></pre>
  
  <p>This doesn't seem to work: the values array passed to <em>FooBarConverter</em> contains <code>DependencyProperty.UnsetValue</code> for each value (two, in this case). Removing the converters on the child bindings (<em>FooConverter</em> and <em>BarConverter</em>) gives me the actual values. By the way: those converters are properly invoked, it just looks like their result is discarded.</p>
  
  <p>Is this intended behavior? I want to bind 2 properties by I need to convert at least one of them before throwing them into the <code>MultiValueConverter</code>...</p>