title: wp_nav_menu() not adding .menu-item and similar classes?
body: <p>According to the Codex at <a href="http://codex.wordpress.org/wp_nav_menu" rel="nofollow">http://codex.wordpress.org/wp_nav_menu</a>, </p>
  
  <p>the following classes <strong>should be applied to &lt;li&gt; menu-item elements generated by wp_nav_menu():</strong></p>
  
  <ul>
  <li>.menu-item  (all &lt;li&gt;'s )</li>
  <li>.menu-item-has-children (where applicable)</li>
  <li>.current-menu-item (where applicable)</li>
  <li>.current-menu-parent (where applicable)</li>
  <li>.menu-item-home (if there is a link to site's front page.</li>
  </ul>
  
  <p><strong>However, I'm not seeing any of these</strong> -- not on the theme I'm working on, nor on twentythirteen, twentyfouteen, or underscores.</p>
  
  <p>Instead, I'm only seeing the classes that are listed as only being present for backwards compatibility with the old wp_page_menu() output:</p>
  
  <ul>
  <li>.page_item</li>
  <li>.page_item_{id}</li>
  <li>.current_page_item</li>
  <li>.page_item_has_children</li>
  </ul>
  
  <p>I can't find any code or filters in any of the three themes I checked that would override the default class behavior, nor do I have any such code in my own theme. </p>
  
  <p>Am I missing something incredibly obvious here? The fact that I can't find anyone else asking why these calsses aren't showing up makes me think that I might be. <strong>Is there something else that I need to do</strong> to get the "standard" CSS styling classes to show up?</p>
  
  <p>I'm on <strong>WordPress 3.8</strong></p>
  
  <p><strong>header.php has:</strong></p>
  
  <pre><code>wp_nav_menu( array( 'theme_location' =&gt; 'primarynav' ) ); 
  </code></pre>
  
  <p><strong>functions.php setup function has:</strong></p>
  
  <pre><code>register_nav_menus( array(
      'primarynav' =&gt; __( 'Primary Site Navigation', 'newthemetextdomain' ),
  ) );
  </code></pre>
  
  <p><strong>HTML output (excerpt</strong> -- I'm using test data, so the nav menu is more extensive than it would be in production) </p>
  
  <pre><code>&lt;li class="page_item page-item-174 page_item_has_children current_page_ancestor current_page_parent"&gt;
      &lt;a href="http://127.0.0.1/DevWP/?page_id=174"&gt;Level 1&lt;/a&gt;
      &lt;ul class='children'&gt;
          &lt;li class="page_item page-item-173 page_item_has_children"&gt;
              &lt;a href="http://127.0.0.1/DevWP/?page_id=173"&gt;Level 2&lt;/a&gt;
              &lt;ul class='children'&gt;
                &lt;li class="page_item page-item-172"&gt;
                    &lt;a href="http://127.0.0.1/DevWP/?page_id=172"&gt;Level 3&lt;/a&gt;
                &lt;/li&gt;
                &lt;li class="page_item page-item-746"&gt;
                    &lt;a href="http://127.0.0.1/DevWP/?page_id=746"&gt;Level 3a&lt;/a&gt;
                &lt;/li&gt;
                &lt;li class="page_item page-item-748"&gt;
                    &lt;a href="http://127.0.0.1/DevWP/?page_id=748"&gt;Level 3b&lt;/a&gt;
                &lt;/li&gt;
            &lt;/ul&gt;
        &lt;/li&gt;
        &lt;li class="page_item page-item-742 current_page_item"&gt;
            &lt;a href="http://127.0.0.1/DevWP/?page_id=742"&gt;Level 2a&lt;/a&gt;
        &lt;/li&gt;
  </code></pre>