diff --git a/source b/source
index 9e11deef691..2c2da4a44eb 100644
--- a/source
+++ b/source
@@ -82283,7 +82283,9 @@ dictionary <dfn dictionary>DragEventInit</dfn> : <span>MouseEventInit</span> {
     <ol>
      <li><p>Set <var>element</var>'s <span>previously focused element</span> to null.</p></li>
 
-     <li><p>If <var>focusPreviousElement</var> is true, then run the <span>focusing steps</span> for
+     <li><p>If <var>focusPreviousElement</var> is true and <var>document</var>'s <span>focused area
+     of the document</span>'s <span>DOM anchor</span> is a <span>shadow-including inclusive
+     descendant</span> of <var>element</var>, then run the <span>focusing steps</span> for
      <var>previouslyFocusedElement</var>; the viewport should not be scrolled by doing this
      step.</p></li>
     </ol>