diff --git a/mozilla/dom/src/base/nsDOMClassInfo.cpp b/mozilla/dom/src/base/nsDOMClassInfo.cpp
index a497550bc9e..cd2076a8e46 100644
--- a/mozilla/dom/src/base/nsDOMClassInfo.cpp
+++ b/mozilla/dom/src/base/nsDOMClassInfo.cpp
@@ -1969,6 +1969,7 @@ nsDOMClassInfo::Init()
   DOM_CLASSINFO_MAP_BEGIN(XULElement, nsIDOMXULElement)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMXULElement)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMEventTarget)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOM3Node)
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN(XULCommandDispatcher, nsIDOMXULCommandDispatcher)