diff --git a/index.html b/index.html
index 545a249..087781d 100644
--- a/index.html
+++ b/index.html
@@ -239,6 +239,9 @@ <h2><code>pointerlockchange</code> and <code>pointerlockerror</code> Events</h2>
       href="http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-node-document">
       node document</a>.</p>
 
+      <p>These events are not cancelable. The value of the events' <code>defaultPrevented</code>
+      attribute [[!DOM4]] has no effect.</p>
+
       <p class="note">Magnification software increases the size of content on
       the screen.  It uses the mouse to move the magnified point of focus
       around.  When a pointer lock is initiated, the magnification software