diff --git a/mozilla/layout/base/nsCSSFrameConstructor.cpp b/mozilla/layout/base/nsCSSFrameConstructor.cpp
index 63aa0b61ee0..4b31d291426 100644
--- a/mozilla/layout/base/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/base/nsCSSFrameConstructor.cpp
@@ -5713,7 +5713,15 @@ nsCSSFrameConstructor::ContentInserted(nsIPresContext* aPresContext,
         // Convert to a tree row group frame.
         nsTreeRowGroupFrame* treeRowGroup = (nsTreeRowGroupFrame*)parentFrame;
         if (treeRowGroup && treeRowGroup->IsLazy()) {
-          treeRowGroup->OnContentAdded(*aPresContext);
+          nsIFrame* nextSibling = FindNextSibling(shell, aContainer, aIndexInContainer);
+		  if(!nextSibling)
+            treeRowGroup->OnContentAdded(*aPresContext);
+		  else {
+            nsIFrame*     frame = GetFrameFor(shell, aPresContext, aContainer);
+            nsTreeRowGroupFrame* frameTreeRowGroup = (nsTreeRowGroupFrame*)frame;
+			if(frameTreeRowGroup)
+              frameTreeRowGroup->OnContentInserted(*aPresContext, nextSibling);
+		  }
           return NS_OK;
         }
       }
diff --git a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
index 63aa0b61ee0..4b31d291426 100644
--- a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -5713,7 +5713,15 @@ nsCSSFrameConstructor::ContentInserted(nsIPresContext* aPresContext,
         // Convert to a tree row group frame.
         nsTreeRowGroupFrame* treeRowGroup = (nsTreeRowGroupFrame*)parentFrame;
         if (treeRowGroup && treeRowGroup->IsLazy()) {
-          treeRowGroup->OnContentAdded(*aPresContext);
+          nsIFrame* nextSibling = FindNextSibling(shell, aContainer, aIndexInContainer);
+		  if(!nextSibling)
+            treeRowGroup->OnContentAdded(*aPresContext);
+		  else {
+            nsIFrame*     frame = GetFrameFor(shell, aPresContext, aContainer);
+            nsTreeRowGroupFrame* frameTreeRowGroup = (nsTreeRowGroupFrame*)frame;
+			if(frameTreeRowGroup)
+              frameTreeRowGroup->OnContentInserted(*aPresContext, nextSibling);
+		  }
           return NS_OK;
         }
       }
diff --git a/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp b/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp
index ec6ccf503da..69f6730cd1e 100644
--- a/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp
@@ -1129,6 +1129,25 @@ void nsTreeRowGroupFrame::OnContentAdded(nsIPresContext& aPresContext)
   }
 }
 
+void nsTreeRowGroupFrame::OnContentInserted(nsIPresContext& aPresContext, nsIFrame* aNextSibling)
+{
+  nsIFrame* currFrame = aNextSibling;
+
+  if(aNextSibling == mTopFrame)
+    mTopFrame = nsnull;
+
+  while (currFrame) {
+    nsIFrame* nextFrame;
+    currFrame->GetNextSibling(&nextFrame);
+    mFrameConstructor->RemoveMappingsForFrameSubtree(&aPresContext, currFrame);
+    mFrames.DestroyFrame(aPresContext, currFrame);
+    currFrame = nextFrame;
+    //printf("Nuked one off the end.\n");
+  }
+  OnContentAdded(aPresContext);
+	
+}
+
 void nsTreeRowGroupFrame::OnContentRemoved(nsIPresContext& aPresContext, 
                                            nsIFrame* aChildFrame)
 {
diff --git a/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.h b/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.h
index cedb46ad861..93488607b55 100644
--- a/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.h
+++ b/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.h
@@ -62,6 +62,7 @@ public:
 
   // Responses to changes
   void OnContentAdded(nsIPresContext& aPresContext);
+  void OnContentInserted(nsIPresContext& aPresContext, nsIFrame* aNextSibling);
   void OnContentRemoved(nsIPresContext& aPresContext, nsIFrame* aChildFrame);
 
   virtual nsIFrame* GetFirstFrame();