diff --git a/content/base/src/nsTextNode.cpp b/content/base/src/nsTextNode.cpp
index 7d48e41acb2..077ecde84e0 100644
--- a/content/base/src/nsTextNode.cpp
+++ b/content/base/src/nsTextNode.cpp
@@ -112,6 +112,7 @@ public:
                               PRBool aNullParent = PR_TRUE);
 
   NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
+  NS_DECL_NSIMUTATIONOBSERVER_NODEWILLBEDESTROYED
 
   virtual nsGenericDOMDataNode *CloneDataNode(nsINodeInfo *aNodeInfo,
                                               PRBool aCloneText) const
@@ -358,6 +359,13 @@ nsAttributeTextNode::AttributeChanged(nsIDocument* aDocument,
   }
 }
 
+void
+nsAttributeTextNode::NodeWillBeDestroyed(const nsINode* aNode)
+{
+  NS_ASSERTION(aNode == static_cast<nsINode*>(mGrandparent), "Wrong node!");
+  mGrandparent = nsnull;
+}
+
 void
 nsAttributeTextNode::UpdateText(PRBool aNotify)
 {