diff --git a/dom.bs b/dom.bs
index 5a6171625..49cd89ae7 100644
--- a/dom.bs
+++ b/dom.bs
@@ -6769,7 +6769,8 @@ invoked, must run these steps:
 
  <li>
   <p>If <a>context object</a>'s <a for=Element>local name</a> is a
-  <a>valid custom element name</a>, then:
+  <a>valid custom element name</a>, or <a>context object</a>'s
+  <a for=Element><code>is</code> value</a> is not null, then:
 
   <ol>
    <li><p>Let <var>definition</var> be the result of