diff --git a/mozilla/content/base/src/nsContentList.cpp b/mozilla/content/base/src/nsContentList.cpp
index 711d1bd7ad1..41a852c3820 100644
--- a/mozilla/content/base/src/nsContentList.cpp
+++ b/mozilla/content/base/src/nsContentList.cpp
@@ -55,6 +55,9 @@
 
 #include "pldhash.h"
 
+
+static nsIContentList *gCachedContentList;
+
 nsBaseContentList::nsBaseContentList()
 {
   NS_INIT_REFCNT();
@@ -135,6 +138,14 @@ nsBaseContentList::Reset()
   return NS_OK;
 }
 
+// static
+void
+nsBaseContentList::Shutdown()
+{
+  NS_IF_RELEASE(gCachedContentList);
+}
+
+
 // nsFormContentList
 
 // This helper function checks if aContent is in some way associated
@@ -375,7 +386,19 @@ NS_GetContentList(nsIDocument* aDocument, nsIAtom* aMatchAtom,
 
   *aInstancePtrResult = list;
   NS_ADDREF(*aInstancePtrResult);
-                               
+
+  // Hold on to the last requested content list to avoid having it be
+  // removed from the cache immediately when it's released. Avoid
+  // bumping the refcount on the list if the requested list is the one
+  // that's already cached.
+
+  if (gCachedContentList != list) {
+    NS_IF_RELEASE(gCachedContentList);
+
+    gCachedContentList = list;
+    NS_ADDREF(gCachedContentList);
+  }
+
   return NS_OK;
 }
 
diff --git a/mozilla/content/base/src/nsContentList.h b/mozilla/content/base/src/nsContentList.h
index 0a29880d60a..aa7a86359a5 100644
--- a/mozilla/content/base/src/nsContentList.h
+++ b/mozilla/content/base/src/nsContentList.h
@@ -69,6 +69,8 @@ public:
   NS_IMETHOD IndexOf(nsIContent *aContent, PRInt32& aIndex);
   NS_IMETHOD Reset();
 
+  static void Shutdown();
+
 protected:
   nsAutoVoidArray mElements;
 };
diff --git a/mozilla/content/build/nsContentModule.cpp b/mozilla/content/build/nsContentModule.cpp
index 0687974c45f..aaa1925465b 100644
--- a/mozilla/content/build/nsContentModule.cpp
+++ b/mozilla/content/build/nsContentModule.cpp
@@ -107,6 +107,7 @@
 #include "nsRuleNode.h"
 #include "nsWyciwygProtocolHandler.h"
 #include "nsContentAreaDragDrop.h"
+#include "nsContentList.h"
 
 
 class nsIDocumentLoaderFactory;
@@ -233,6 +234,7 @@ Shutdown(nsIModule* aSelf)
   nsGenericElement::Shutdown();
   nsGenericDOMDataNode::Shutdown();
   nsEventListenerManager::Shutdown();
+  nsContentList::Shutdown();
   nsComputedDOMStyle::Shutdown();
 
   // Release all of our atoms