Docs: Clarify use of aria-current in navigation treeview example

content/patterns/treeview/examples/treeview-navigation.html

@@ -72,7 +72,7 @@
             If the scope of the header element were body, browsers would automatically treat the header as an ARIA banner,
             so the header would not need the role="banner". -->
           <div class="page">
             <header role="banner">
               <div class="title" id="id_website_title">Mythical University</div>
               <div class="tagline">Using a Tree widget pattern for navigation links</div>
             </header>
@@ -293,7 +293,7 @@
 
               <!-- NOTE: In a real website the following SECTION element should be MAIN element -->
               <section class="main" aria-labelledby="id_website_title id_page_title">
                 <h1 class="page_title" id="id_page_title">Mythical University</h1>
                 <div class="content">
                   <p></p>
                 </div>
@@ -302,7 +302,7 @@
             <!-- NOTE: In a real website the footer element would be a top level element, i.e., it would have the body as its scope.
             If the scope of the footer element were body, browsers would automatically treat the header as an ARIA contentinfo,
             so the footer would not need the role="contentinfo". -->
             <footer role="contentinfo">Mythical University footer information</footer>
           </div>
         </div>
         <div role="separator" id="ex_end_sep" aria-labelledby="ex_end_sep ex_label" aria-label="End of"></div>
@@ -347,8 +347,16 @@
               <li>When focus leaves the tree, if the item representing the current page is in a branch that has been collapsed, that branch is expanded to ensure the current page item is both visible and exposed as active to assistive technologies.</li>
             </ul>
           </li>
-        </ul>
-        <h3>Visual design and high contrast features</h3>
+        </ul>
+        <p>
+          In this navigation example, the
+          <a href="https://www.w3.org/TR/wai-aria-1.2/#aria-current" class="property-reference"><code>aria-current</code></a>
+          attribute is used instead of
+          <a href="https://www.w3.org/TR/wai-aria-1.2/#aria-selected" class="property-reference"><code>aria-selected</code></a>
+          because it more clearly communicates which page is currently displayed.
+          The ARIA Tree View pattern does not require that an item be selected.
+        </p>
+        <h3>Visual design and high contrast features</h3>
         <ul>
           <li>To help communicate that the arrow keys are available for navigation within the tree, a border is added to the tree container when focus is within the tree.</li>
           <li>