Add notes to 2.4.3 understanding to try and address static content receiving focus and what does/doesn't constitute a focus order failure

understanding/20/focus-order.html

@@ -17,8 +17,8 @@ <h2>In brief</h2>
       </dl>
 
    </section>
-   
-   <section id="intent">
+
+  <section id="intent">
       <h2>Intent of Focus Order</h2>
 
       <p>The intent of this success criterion is to ensure that when users navigate sequentially
@@ -62,30 +62,50 @@ <h2>Intent of Focus Order</h2>
          sets of users and does not appear to either of them to jump around randomly. 
       </p>
 
+      <p>Focus order needs to allow the user to navigate focusable elements in a logical order,
+         and that order needs to preserve any meaning or operation that the page is conveying. 
+         Focus order does not necessarily need to follow the visual layout of the web page,
+         as long as the order in which elements receive focus is logical, and the hierarchy and relationship
+         of content implied by the visual presentation is preserved. For instance, in a two-column
+         layout, the assumption in western left-to-right systems may be that focus moves through the elements in the
+         left-hand column first, from the top to the bottom of the column, and then proceed to the right-hand column.
+         However, if the two columns are independent of each other, and meaning/operation are not affected, it is not
+         a failure if elements in the right-hand column receive focus first, followed by the elements in the left-hand column.
+         As a best practice, though, make sure the focus order reinforces the reading order implied by the visual layout.
+      </p>
+
+      <div class="note">
+        <p>This requirement does not specify what should or should not receive focus, but rather assesses the order in which elements receive focus. This success criterion does not prohibit making non-operable content (e.g., static text) focusable, or programmatically moving focus to such content. However, it is a failure of Focus Order if items receive focus in an order that impedes the meaning or operation of content, or creates confusing or illogical focus orders — for example,
+         a control appearing to receive focus multiple times due to the use of nested focusable elements.</p>
+         <pre><code class="language-html">&lt;div tabindex="0"&gt;&lt;button&gt;...&lt;/button&gt;&lt;/div&gt;</code></pre>
+         <p>As a best practice, avoid having focusable elements which cannot be operated
+         or actioned, as these are likely to make operation tedious for keyboard users.</p>
+      </div>
+
       <p>For clarity:</p>
 
       <ul>
 
          <li>Focusable components need to receive focus in an order that preserves meaning and
-            operability only when navigation sequences affect meaning and operability.
+            operability.
          </li>
 
-         <li>In those cases where it is required, there may be more than one order that will preserve
-            meaning and operability.
-         </li>
+         <li>Focus order does not necessarily need to follow the visual presentation or layout.</li>
 
          <li>If there is more than one order that preserves meaning and operability, only one of
             them needs to be provided.
          </li>
 
+         <li>Static/non-interactive elements can receive focus, as long as they don't
+            impede operation of the content, or result in confusing or illogical focus order.
+         </li>
+
       </ul>
-
-
+
    </section>
    <section id="benefits">
       <h2>Benefits of Focus Order</h2>
 
-
       <p>These techniques benefit keyboard users who navigate documents sequentially and expect
          the focus order to be consistent with the sequential reading order.
       </p>
@@ -180,7 +200,6 @@ <h2>Examples of Focus Order</h2>
    <section id="resources">
       <h2>Resources for Focus Order</h2>
 
-
    </section>
 
    {% # Data for associated techniques is defined in understanding/understanding.11tydata.js %}