diff --git a/spec/shadow/index.html b/spec/shadow/index.html
index 972bc2be..d4c5abee 100644
--- a/spec/shadow/index.html
+++ b/spec/shadow/index.html
@@ -844,30 +844,14 @@ <h3>Inertness of HTML Elements in a shadow tree</h3>
           We must fill this gap because we expect that most of HTML Elements behave in the same way as <a>in a document</a>, as long as they are <a>in a shadow-including document</a>.
           See W3C <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=26365">Bug 26365</a> and <a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=27406">Bug 27406</a> for the details.
           The following is the tentative summary of the discussions in the W3C bugs. We, however, haven't covered all HTML Elements and their behaviors here yet.
-          For HTML Elements which are not explicitly stated here, they should be considered as <a>active in a shadow tree</a>.
+          For HTML Elements which are not explicitly stated here, they should *work* even in a shadow tree.
           We are trying to update [[!HTML]] itself, instead of having monkey patches here.
+          If [[!HTML]] explains an element's behavior explicitly, it should be honored, instead of this section.
         </p>
         <p>
-          HTML Elements are classified into the following categories:
+          Some HTML Elements are classified into the following categories:
         </p>
         <ul>
-          <li>
-            <p>
-              <dfn>Active in a shadow tree</dfn>
-            </p>
-            <p>
-              A subset of <a>HTML elements</a> which <strong>must</strong> behave as if they were in the <a>document tree</a>, even when they participate in a <a>shadow tree</a>,
-              as long as they are <a>in a shadow-including document</a>.
-            </p>
-            <p>
-              The following HTML elements <strong>must</strong> be classified to this category:
-            </p>
-            <ul>
-              <li><code>dialog</code></li>
-              <li><code>iframe</code></li>
-              <li><code>style</code></li>
-            </ul>
-          </li>
           <li>
             <p>
               <dfn>Inert in a shadow tree</dfn>:
@@ -882,6 +866,7 @@ <h3>Inertness of HTML Elements in a shadow tree</h3>
             <ul>
               <li><a data-lt="base element"><code>base</code></a></li>
               <li><a data-lt="link element"><code>link</code></a></li>
+              <li><code>meta</code></li>
             </ul>
           </li>
           <li>