diff --git a/content/xul/templates/public/nsIXULSortService.idl b/content/xul/templates/public/nsIXULSortService.idl
index 0ec8dd10735e..0243c476d0c0 100755
--- a/content/xul/templates/public/nsIXULSortService.idl
+++ b/content/xul/templates/public/nsIXULSortService.idl
@@ -25,7 +25,7 @@
 #include "nsIRDFResource.idl"
 
 
-[ptr] native nsIRDFResourceArray( nsIRDFResource *);
+[ptr] native nsIRDFDataSourceHandle( nsIRDFDataSource *);
 
 interface nsIContent;
 interface nsIDOMNode;
@@ -35,7 +35,7 @@ interface nsIDOMNode;
 interface nsIXULSortService : nsISupports
 {
 		void	Sort(in nsIDOMNode node, in string sortResource, in string sortDirection);
-[noscript]	void	InsertContainerNode(in nsIRDFCompositeDataSource db, in nsIRDFDataSource cache, in nsIContent root, in nsIContent trueParent,
+[noscript]	void	InsertContainerNode(in nsIRDFCompositeDataSource db, in nsIRDFDataSourceHandle cacheHandle, in nsIContent root, in nsIContent trueParent,
 				in nsIContent container, in nsIContent node, in boolean aNotify);
 };
 
diff --git a/content/xul/templates/src/nsXULSortService.cpp b/content/xul/templates/src/nsXULSortService.cpp
index 0a4fee695cc6..905ed357bae1 100644
--- a/content/xul/templates/src/nsXULSortService.cpp
+++ b/content/xul/templates/src/nsXULSortService.cpp
@@ -1438,7 +1438,7 @@ XULSortServiceImpl::SortTreeChildren(nsIContent *container, sortPtr sortInfo)
 
 
 NS_IMETHODIMP
-XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDataSource *cache, nsIContent *root,
+XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDataSource **cacheHandle, nsIContent *root,
 					nsIContent *trueParent, nsIContent *container, nsIContent *node, PRBool aNotify)
 {
 	nsresult	rv;
@@ -1449,7 +1449,6 @@ XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDat
 	sortInfo.rdfService = gRDFService;
 	sortInfo.db = db;
 	sortInfo.resCache = nsnull;
-	sortInfo.mInner = cache;			/* can be null */
 	sortInfo.colIndex = -1;
 	sortInfo.parentContainer = trueParent;
 	sortInfo.kTreeCellAtom = kTreeCellAtom;
@@ -1457,6 +1456,14 @@ XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDat
 	sortInfo.sortProperty = nsnull;
 	sortInfo.sortProperty2 = nsnull;
 	sortInfo.inbetweenSeparatorSort = PR_FALSE;
+	if (cacheHandle != nsnull)
+	{
+		sortInfo.mInner = *cacheHandle;		// Note: this can/might be null
+	}
+	else
+	{
+		sortInfo.mInner = nsnull;
+	}
 
 	PRBool			sortInfoAvailable = PR_FALSE;
 
@@ -1625,6 +1632,12 @@ XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDat
 	{
 		container->AppendChildTo(node, aNotify);
 	}
+
+	if ((cacheHandle) && (sortInfo.mInner) && ((*cacheHandle) != sortInfo.mInner))
+	{
+		*cacheHandle = sortInfo.mInner;
+		NS_ADDREF(*cacheHandle);
+	}
 	return(NS_OK);
 }
 
diff --git a/content/xul/templates/src/nsXULTemplateBuilder.cpp b/content/xul/templates/src/nsXULTemplateBuilder.cpp
index 647d869cf0b6..eaae9f543e42 100644
--- a/content/xul/templates/src/nsXULTemplateBuilder.cpp
+++ b/content/xul/templates/src/nsXULTemplateBuilder.cpp
@@ -597,9 +597,6 @@ RDFGenericBuilderImpl::Init()
                                           (nsISupports**) &gXULSortService);
         if (NS_FAILED(rv)) return rv;
 
-	rv = nsComponentManager::CreateInstance(kRDFInMemoryDataSourceCID,
-		nsnull, nsIRDFDataSource::GetIID(), (void **)&mCache);
-
         rv = nsComponentManager::CreateInstance(kHTMLElementFactoryCID,
                                                 nsnull,
                                                 kIHTMLElementFactoryIID,
@@ -726,9 +723,6 @@ RDFGenericBuilderImpl::SetRootContent(nsIContent* aElement)
     {
     	// flush (delete) the cache when re-rerooting the generated content
     	mCache = nsnull;
-    	// and then re-create a new, empty cache
-	nsComponentManager::CreateInstance(kRDFInMemoryDataSourceCID,
-		nsnull, nsIRDFDataSource::GetIID(), (void **)&mCache);
     }
     
     return NS_OK;
@@ -1212,7 +1206,16 @@ RDFGenericBuilderImpl::OnChange(nsIRDFResource* aSource,
 
 	if (mCache)
 	{
-		mCache->Change(aSource, aProperty, aOldTarget, aNewTarget);
+		if (aOldTarget)
+		{
+			// XXX fix this: in-memory DS doesn't like a null oldTarget
+			mCache->Change(aSource, aProperty, aOldTarget, aNewTarget);
+		}
+		else
+		{
+			// XXX should get tv via observer interface
+			mCache->Assert(aSource, aProperty, aNewTarget, PR_TRUE);
+		}
 	}
 
     nsCOMPtr<nsISupportsArray> elements;
@@ -2063,8 +2066,14 @@ RDFGenericBuilderImpl::BuildContentFromTemplate(nsIContent *aTemplateNode,
                 rv = NS_ERROR_UNEXPECTED;
 
                 if (gXULSortService && isResourceElement) {
-                    rv = gXULSortService->InsertContainerNode(mDB, mCache,
+			nsCOMPtr<nsIRDFDataSource>		tempCache = nsnull;
+
+                    rv = gXULSortService->InsertContainerNode(mDB, getter_AddRefs(tempCache),
                     	mRoot, trueParent, aRealNode, realKid, aNotify);
+                    if (tempCache)
+                    {
+                    	mCache = tempCache;
+                    }
                 }
 
                 if (NS_FAILED(rv)) {
diff --git a/rdf/base/idl/nsIXULSortService.idl b/rdf/base/idl/nsIXULSortService.idl
index 0ec8dd10735e..0243c476d0c0 100755
--- a/rdf/base/idl/nsIXULSortService.idl
+++ b/rdf/base/idl/nsIXULSortService.idl
@@ -25,7 +25,7 @@
 #include "nsIRDFResource.idl"
 
 
-[ptr] native nsIRDFResourceArray( nsIRDFResource *);
+[ptr] native nsIRDFDataSourceHandle( nsIRDFDataSource *);
 
 interface nsIContent;
 interface nsIDOMNode;
@@ -35,7 +35,7 @@ interface nsIDOMNode;
 interface nsIXULSortService : nsISupports
 {
 		void	Sort(in nsIDOMNode node, in string sortResource, in string sortDirection);
-[noscript]	void	InsertContainerNode(in nsIRDFCompositeDataSource db, in nsIRDFDataSource cache, in nsIContent root, in nsIContent trueParent,
+[noscript]	void	InsertContainerNode(in nsIRDFCompositeDataSource db, in nsIRDFDataSourceHandle cacheHandle, in nsIContent root, in nsIContent trueParent,
 				in nsIContent container, in nsIContent node, in boolean aNotify);
 };
 
diff --git a/rdf/content/src/nsRDFGenericBuilder.cpp b/rdf/content/src/nsRDFGenericBuilder.cpp
index 647d869cf0b6..eaae9f543e42 100644
--- a/rdf/content/src/nsRDFGenericBuilder.cpp
+++ b/rdf/content/src/nsRDFGenericBuilder.cpp
@@ -597,9 +597,6 @@ RDFGenericBuilderImpl::Init()
                                           (nsISupports**) &gXULSortService);
         if (NS_FAILED(rv)) return rv;
 
-	rv = nsComponentManager::CreateInstance(kRDFInMemoryDataSourceCID,
-		nsnull, nsIRDFDataSource::GetIID(), (void **)&mCache);
-
         rv = nsComponentManager::CreateInstance(kHTMLElementFactoryCID,
                                                 nsnull,
                                                 kIHTMLElementFactoryIID,
@@ -726,9 +723,6 @@ RDFGenericBuilderImpl::SetRootContent(nsIContent* aElement)
     {
     	// flush (delete) the cache when re-rerooting the generated content
     	mCache = nsnull;
-    	// and then re-create a new, empty cache
-	nsComponentManager::CreateInstance(kRDFInMemoryDataSourceCID,
-		nsnull, nsIRDFDataSource::GetIID(), (void **)&mCache);
     }
     
     return NS_OK;
@@ -1212,7 +1206,16 @@ RDFGenericBuilderImpl::OnChange(nsIRDFResource* aSource,
 
 	if (mCache)
 	{
-		mCache->Change(aSource, aProperty, aOldTarget, aNewTarget);
+		if (aOldTarget)
+		{
+			// XXX fix this: in-memory DS doesn't like a null oldTarget
+			mCache->Change(aSource, aProperty, aOldTarget, aNewTarget);
+		}
+		else
+		{
+			// XXX should get tv via observer interface
+			mCache->Assert(aSource, aProperty, aNewTarget, PR_TRUE);
+		}
 	}
 
     nsCOMPtr<nsISupportsArray> elements;
@@ -2063,8 +2066,14 @@ RDFGenericBuilderImpl::BuildContentFromTemplate(nsIContent *aTemplateNode,
                 rv = NS_ERROR_UNEXPECTED;
 
                 if (gXULSortService && isResourceElement) {
-                    rv = gXULSortService->InsertContainerNode(mDB, mCache,
+			nsCOMPtr<nsIRDFDataSource>		tempCache = nsnull;
+
+                    rv = gXULSortService->InsertContainerNode(mDB, getter_AddRefs(tempCache),
                     	mRoot, trueParent, aRealNode, realKid, aNotify);
+                    if (tempCache)
+                    {
+                    	mCache = tempCache;
+                    }
                 }
 
                 if (NS_FAILED(rv)) {
diff --git a/rdf/content/src/nsXULSortService.cpp b/rdf/content/src/nsXULSortService.cpp
index 0a4fee695cc6..905ed357bae1 100644
--- a/rdf/content/src/nsXULSortService.cpp
+++ b/rdf/content/src/nsXULSortService.cpp
@@ -1438,7 +1438,7 @@ XULSortServiceImpl::SortTreeChildren(nsIContent *container, sortPtr sortInfo)
 
 
 NS_IMETHODIMP
-XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDataSource *cache, nsIContent *root,
+XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDataSource **cacheHandle, nsIContent *root,
 					nsIContent *trueParent, nsIContent *container, nsIContent *node, PRBool aNotify)
 {
 	nsresult	rv;
@@ -1449,7 +1449,6 @@ XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDat
 	sortInfo.rdfService = gRDFService;
 	sortInfo.db = db;
 	sortInfo.resCache = nsnull;
-	sortInfo.mInner = cache;			/* can be null */
 	sortInfo.colIndex = -1;
 	sortInfo.parentContainer = trueParent;
 	sortInfo.kTreeCellAtom = kTreeCellAtom;
@@ -1457,6 +1456,14 @@ XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDat
 	sortInfo.sortProperty = nsnull;
 	sortInfo.sortProperty2 = nsnull;
 	sortInfo.inbetweenSeparatorSort = PR_FALSE;
+	if (cacheHandle != nsnull)
+	{
+		sortInfo.mInner = *cacheHandle;		// Note: this can/might be null
+	}
+	else
+	{
+		sortInfo.mInner = nsnull;
+	}
 
 	PRBool			sortInfoAvailable = PR_FALSE;
 
@@ -1625,6 +1632,12 @@ XULSortServiceImpl::InsertContainerNode(nsIRDFCompositeDataSource *db, nsIRDFDat
 	{
 		container->AppendChildTo(node, aNotify);
 	}
+
+	if ((cacheHandle) && (sortInfo.mInner) && ((*cacheHandle) != sortInfo.mInner))
+	{
+		*cacheHandle = sortInfo.mInner;
+		NS_ADDREF(*cacheHandle);
+	}
 	return(NS_OK);
 }
 
diff --git a/rdf/content/src/nsXULTemplateBuilder.cpp b/rdf/content/src/nsXULTemplateBuilder.cpp
index 647d869cf0b6..eaae9f543e42 100644
--- a/rdf/content/src/nsXULTemplateBuilder.cpp
+++ b/rdf/content/src/nsXULTemplateBuilder.cpp
@@ -597,9 +597,6 @@ RDFGenericBuilderImpl::Init()
                                           (nsISupports**) &gXULSortService);
         if (NS_FAILED(rv)) return rv;
 
-	rv = nsComponentManager::CreateInstance(kRDFInMemoryDataSourceCID,
-		nsnull, nsIRDFDataSource::GetIID(), (void **)&mCache);
-
         rv = nsComponentManager::CreateInstance(kHTMLElementFactoryCID,
                                                 nsnull,
                                                 kIHTMLElementFactoryIID,
@@ -726,9 +723,6 @@ RDFGenericBuilderImpl::SetRootContent(nsIContent* aElement)
     {
     	// flush (delete) the cache when re-rerooting the generated content
     	mCache = nsnull;
-    	// and then re-create a new, empty cache
-	nsComponentManager::CreateInstance(kRDFInMemoryDataSourceCID,
-		nsnull, nsIRDFDataSource::GetIID(), (void **)&mCache);
     }
     
     return NS_OK;
@@ -1212,7 +1206,16 @@ RDFGenericBuilderImpl::OnChange(nsIRDFResource* aSource,
 
 	if (mCache)
 	{
-		mCache->Change(aSource, aProperty, aOldTarget, aNewTarget);
+		if (aOldTarget)
+		{
+			// XXX fix this: in-memory DS doesn't like a null oldTarget
+			mCache->Change(aSource, aProperty, aOldTarget, aNewTarget);
+		}
+		else
+		{
+			// XXX should get tv via observer interface
+			mCache->Assert(aSource, aProperty, aNewTarget, PR_TRUE);
+		}
 	}
 
     nsCOMPtr<nsISupportsArray> elements;
@@ -2063,8 +2066,14 @@ RDFGenericBuilderImpl::BuildContentFromTemplate(nsIContent *aTemplateNode,
                 rv = NS_ERROR_UNEXPECTED;
 
                 if (gXULSortService && isResourceElement) {
-                    rv = gXULSortService->InsertContainerNode(mDB, mCache,
+			nsCOMPtr<nsIRDFDataSource>		tempCache = nsnull;
+
+                    rv = gXULSortService->InsertContainerNode(mDB, getter_AddRefs(tempCache),
                     	mRoot, trueParent, aRealNode, realKid, aNotify);
+                    if (tempCache)
+                    {
+                    	mCache = tempCache;
+                    }
                 }
 
                 if (NS_FAILED(rv)) {