diff --git a/mozilla/content/base/src/nsDocumentFragment.cpp b/mozilla/content/base/src/nsDocumentFragment.cpp
index 3d46d541b7b..0b9a346377c 100644
--- a/mozilla/content/base/src/nsDocumentFragment.cpp
+++ b/mozilla/content/base/src/nsDocumentFragment.cpp
@@ -207,6 +207,7 @@ NS_INTERFACE_MAP_BEGIN(nsDocumentFragment)
   NS_INTERFACE_MAP_ENTRY(nsIDOMNode)
   NS_INTERFACE_MAP_ENTRY(nsIDOM3Node)
   NS_INTERFACE_MAP_ENTRY(nsIContent)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMGCParticipant)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIContent)
   NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(DocumentFragment)
 NS_INTERFACE_MAP_END