title: UWP CommandBar dynamic overflow behavior not working
body: <p>On <a href="https://msdn.microsoft.com/en-us/windows/uwp/controls-and-patterns/app-bars" rel="nofollow noreferrer">this page in Windows Dev Center</a> it says </p>
  
  <blockquote>
    <p>The new dynamic overflow behavior will automatically move primary commands into the SecondaryCommands area when space is limited.</p>
  </blockquote>
  
  <p>But in my App there are only 4 Buttons Visible, the 5th one is not there, also not if I open the Menu, I have to put it manually into the <code>SecondaryCommands</code> List, to make Windows showing it.
  <br> I made a plain simple CommandBar to test it</p>
  
  <pre><code>&lt;CommandBar&gt;
      &lt;AppBarButton Icon="Find" Label="test" /&gt;
      &lt;AppBarButton Icon="Find" Label="test" /&gt;
      &lt;AppBarButton Icon="Find" Label="test" /&gt;
      &lt;AppBarButton Icon="Find" Label="test" /&gt;
      &lt;AppBarButton Icon="Find" Label="test" /&gt;
  &lt;/CommandBar&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/lqHgq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lqHgq.png" alt="Screenshot"></a></p>
  
  <p>Build Target and Min Version is 10.0 10586.
  <br> Also I noticed that <code>CommandBarOverflowButtonVisibility</code> and similar properties can't be found.</p>