title: Vue named slots do not work when wrapped
body: <p>I have a responsive-menu component which I want to use named slots inside of this up my template markup:</p>
  
  <pre><code>&lt;template&gt;
      &lt;div class="responsive-menu"&gt;
          &lt;div class="menu-header"&gt;
              &lt;slot name="header"&gt;&lt;/slot&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/template&gt;
  </code></pre>
  
  <p>Whenever I try my named slot like this it work perfectly fine:</p>
  
  <pre><code>&lt;responsive-menu&gt;
      &lt;h3 slot="header"&gt;Responsive menu header&lt;/h3&gt;
  &lt;/responsive-menu&gt;
  </code></pre>
  
  <p>However as soon as I wrap it with a class nothing shows up anymore.</p>
  
  <pre><code>&lt;responsive-menu&gt;
      &lt;div class="container"&gt;
          &lt;h3 slot="header"&gt;Responsive menu header&lt;/h3&gt;
      &lt;/div&gt;
  &lt;/responsive-menu&gt;
  </code></pre>
  
  <p>What is going on here? Shouldn't I just be able to wrap the named component? Which does it appear that my named slots need to be direct children of my Vue component?</p>