diff --git a/reference/dom/domdocument/registernodeclass.xml b/reference/dom/domdocument/registernodeclass.xml
index 7dd5b5e747..301cb90a8b 100644
--- a/reference/dom/domdocument/registernodeclass.xml
+++ b/reference/dom/domdocument/registernodeclass.xml
@@ -174,6 +174,46 @@ var_dump(get_class($child->ownerDocument));
 <![CDATA[
 string(13) "myDOMDocument"
 string(18) "myOtherDOMDocument"
+]]>
+    </screen>
+   </example>
+  </para>
+  <para>
+   <example xml:id="domdocument.registernodeclass.example.transient">
+    <title>Custom objects are transient</title>
+    <caution>
+     <simpara>
+      Objects of the registered node classes are transient, i.e. they are
+      destroyed when they are no longer referenced from PHP code, and recreated
+      when being retrieved again. That implies that custom property values will be
+      lost after recreation.
+     </simpara>
+    </caution>
+    <programlisting role="php">
+<![CDATA[
+<?php
+class MyDOMElement extends DOMElement
+{
+    public $myProp = 'default value';
+}
+
+$doc = new DOMDocument();
+$doc->registerNodeClass('DOMElement', 'MyDOMElement');
+
+$node = $doc->createElement('a');
+$node->myProp = 'modified value';
+$doc->appendChild($node);
+
+echo $doc->childNodes[0]->myProp, PHP_EOL;
+unset($node);
+echo $doc->childNodes[0]->myProp, PHP_EOL;
+?>]]>
+    </programlisting>
+    &example.outputs;
+    <screen role="xml">
+<![CDATA[
+modified value
+default value
 ]]>
     </screen>
    </example>