diff --git a/content/xbl/src/nsXBLBinding.cpp b/content/xbl/src/nsXBLBinding.cpp
index c9408a5d992..dd3a4d425f1 100644
--- a/content/xbl/src/nsXBLBinding.cpp
+++ b/content/xbl/src/nsXBLBinding.cpp
@@ -1294,7 +1294,8 @@ nsXBLBinding::BuildInsertionTable()
 
   PRUint32 count;
   childrenElements->Count(&count);
-  for (PRUint32 i = 0; i < count; i++) {
+  PRUint32 i;
+  for (i = 0; i < count; i++) {
     nsCOMPtr<nsISupports> supp;
     childrenElements->GetElementAt(i, getter_AddRefs(supp));
     nsCOMPtr<nsIContent> child(do_QueryInterface(supp));
@@ -1332,6 +1333,20 @@ nsXBLBinding::BuildInsertionTable()
       }
     }
   }
+
+  // Now remove the <children> elements.
+  for (i = 0; i < count; i++) {
+    nsCOMPtr<nsISupports> supp;
+    childrenElements->GetElementAt(i, getter_AddRefs(supp));
+    nsCOMPtr<nsIContent> child(do_QueryInterface(supp));
+    if (child) {
+      nsCOMPtr<nsIContent> parent; 
+      child->GetParent(*getter_AddRefs(parent));
+      PRInt32 index;
+      parent->IndexOf(child, index);
+      parent->RemoveChildAt(index, PR_FALSE);
+    }
+  }
 }
 
 PRBool
diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index d36a04e44ef..02a96303b83 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -152,7 +152,7 @@ static PRBool gReallyNoisyContentUpdates = PR_FALSE;
 static PRBool gNoisyInlineConstruction = PR_FALSE;
 #endif
 
-//#define XULTREE
+#define XULTREE
 #ifdef XULTREE
 #include "nsXULTreeFrame.h"
 #include "nsXULTreeOuterGroupFrame.h"
@@ -9050,8 +9050,8 @@ nsCSSFrameConstructor::ContentRemoved(nsIPresContext* aPresContext,
             nsBoxLayoutState state(aPresContext);
             treeRowGroup->MarkDirtyChildren(state);
             treeRowGroup->ClearRowGroupInfo();
-            return NS_OK;
           }
+          return NS_OK;
 #else
           nsTreeRowGroupFrame* treeRowGroup = (nsTreeRowGroupFrame*)parentFrame;
           if (treeRowGroup) {
diff --git a/layout/html/forms/src/nsGfxTextControlFrame2.cpp b/layout/html/forms/src/nsGfxTextControlFrame2.cpp
index eb27d4cb03d..d26c04a1b38 100644
--- a/layout/html/forms/src/nsGfxTextControlFrame2.cpp
+++ b/layout/html/forms/src/nsGfxTextControlFrame2.cpp
@@ -1450,7 +1450,7 @@ nsGfxTextControlFrame2::GetPrefSize(nsBoxLayoutState& aState, nsSize& aSize)
   if (!aReflowState)
     return NS_OK;
 
-  if (eReflowReason_Initial == aReflowState->reason)
+  if (mState & NS_FRAME_FIRST_REFLOW)
   {
     nsFormControlFrame::RegUnRegAccessKey(aPresContext, NS_STATIC_CAST(nsIFrame*, this), PR_TRUE);
     nsFormFrame::AddFormControlFrame(aPresContext, *NS_STATIC_CAST(nsIFrame*, this));
diff --git a/layout/html/style/src/nsCSSFrameConstructor.cpp b/layout/html/style/src/nsCSSFrameConstructor.cpp
index d36a04e44ef..02a96303b83 100644
--- a/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -152,7 +152,7 @@ static PRBool gReallyNoisyContentUpdates = PR_FALSE;
 static PRBool gNoisyInlineConstruction = PR_FALSE;
 #endif
 
-//#define XULTREE
+#define XULTREE
 #ifdef XULTREE
 #include "nsXULTreeFrame.h"
 #include "nsXULTreeOuterGroupFrame.h"
@@ -9050,8 +9050,8 @@ nsCSSFrameConstructor::ContentRemoved(nsIPresContext* aPresContext,
             nsBoxLayoutState state(aPresContext);
             treeRowGroup->MarkDirtyChildren(state);
             treeRowGroup->ClearRowGroupInfo();
-            return NS_OK;
           }
+          return NS_OK;
 #else
           nsTreeRowGroupFrame* treeRowGroup = (nsTreeRowGroupFrame*)parentFrame;
           if (treeRowGroup) {
diff --git a/layout/xbl/src/nsXBLBinding.cpp b/layout/xbl/src/nsXBLBinding.cpp
index c9408a5d992..dd3a4d425f1 100644
--- a/layout/xbl/src/nsXBLBinding.cpp
+++ b/layout/xbl/src/nsXBLBinding.cpp
@@ -1294,7 +1294,8 @@ nsXBLBinding::BuildInsertionTable()
 
   PRUint32 count;
   childrenElements->Count(&count);
-  for (PRUint32 i = 0; i < count; i++) {
+  PRUint32 i;
+  for (i = 0; i < count; i++) {
     nsCOMPtr<nsISupports> supp;
     childrenElements->GetElementAt(i, getter_AddRefs(supp));
     nsCOMPtr<nsIContent> child(do_QueryInterface(supp));
@@ -1332,6 +1333,20 @@ nsXBLBinding::BuildInsertionTable()
       }
     }
   }
+
+  // Now remove the <children> elements.
+  for (i = 0; i < count; i++) {
+    nsCOMPtr<nsISupports> supp;
+    childrenElements->GetElementAt(i, getter_AddRefs(supp));
+    nsCOMPtr<nsIContent> child(do_QueryInterface(supp));
+    if (child) {
+      nsCOMPtr<nsIContent> parent; 
+      child->GetParent(*getter_AddRefs(parent));
+      PRInt32 index;
+      parent->IndexOf(child, index);
+      parent->RemoveChildAt(index, PR_FALSE);
+    }
+  }
 }
 
 PRBool
diff --git a/layout/xul/base/src/nsBoxLayout.h b/layout/xul/base/src/nsBoxLayout.h
index d58af01fcae..d72c683692b 100644
--- a/layout/xul/base/src/nsBoxLayout.h
+++ b/layout/xul/base/src/nsBoxLayout.h
@@ -33,6 +33,7 @@ class nsBoxLayout : public nsIBoxLayout {
 public:
 
   nsBoxLayout();
+  virtual ~nsBoxLayout() {};
 
   NS_DECL_ISUPPORTS
 
diff --git a/layout/xul/base/src/nsContainerBox.cpp b/layout/xul/base/src/nsContainerBox.cpp
index f134570d88f..113946a201e 100644
--- a/layout/xul/base/src/nsContainerBox.cpp
+++ b/layout/xul/base/src/nsContainerBox.cpp
@@ -74,6 +74,10 @@ nsContainerBox::nsContainerBox(nsIPresShell* aShell):nsBox(aShell)
   mChildCount = 0;
 }
 
+nsContainerBox::~nsContainerBox()
+{
+}
+
 void
 nsContainerBox::GetBoxName(nsAutoString& aName)
 {
diff --git a/layout/xul/base/src/nsContainerBox.h b/layout/xul/base/src/nsContainerBox.h
index 927ba2060ce..22f1a9d95d3 100644
--- a/layout/xul/base/src/nsContainerBox.h
+++ b/layout/xul/base/src/nsContainerBox.h
@@ -39,6 +39,7 @@ public:
   NS_IMETHOD GetChildBox(nsIBox** aBox);
 
   nsContainerBox(nsIPresShell* aShell);
+  virtual ~nsContainerBox();
 
   NS_IMETHOD SetLayoutManager(nsIBoxLayout* aLayout);
   NS_IMETHOD GetLayoutManager(nsIBoxLayout** aLayout);
@@ -65,8 +66,6 @@ public:
   virtual void SanityCheck(nsFrameList& aFrameList);
   virtual void SetDebugOnChildList(nsBoxLayoutState& aState, nsIBox* aChild, PRBool aDebug);
 
-  virtual ~nsContainerBox() {}
-  
   static nsresult LayoutChildAt(nsBoxLayoutState& aState, nsIBox* aBox, const nsRect& aRect);
 
 
diff --git a/layout/xul/base/src/nsGridLayout.cpp b/layout/xul/base/src/nsGridLayout.cpp
index 50517f3b05e..34ec5c3de2a 100644
--- a/layout/xul/base/src/nsGridLayout.cpp
+++ b/layout/xul/base/src/nsGridLayout.cpp
@@ -87,8 +87,8 @@ nsGridLayout::GetOtherTemple(nsIBox* aBox, nsTempleLayout** aTemple, nsIBox** aT
        child = b;
     }
 
-    nsIBoxLayout* layout = nsnull;
-    child->GetLayoutManager(&layout);
+    nsCOMPtr<nsIBoxLayout> layout;
+    child->GetLayoutManager(getter_AddRefs(layout));
 
     // must find a temple that is not our requestor and is a monument.
     if (layout != aRequestor) {
@@ -186,7 +186,6 @@ nsGridLayout::EnscriptionChanged(nsBoxLayoutState& aState, PRInt32 aIndex)
 NS_IMETHODIMP
 nsGridLayout::DesecrateMonuments(nsIBox* aBox, nsBoxLayoutState& aState)
 {
-  NS_ERROR("Should Never be Called!");
   return NS_OK;
 }
 
diff --git a/layout/xul/base/src/nsIMonument.h b/layout/xul/base/src/nsIMonument.h
index 0eed8d7bba3..2bc1f2e9376 100644
--- a/layout/xul/base/src/nsIMonument.h
+++ b/layout/xul/base/src/nsIMonument.h
@@ -72,7 +72,8 @@ public:
     virtual PRInt32 GetRefCount()=0;
     virtual PRBool SetListener(nsIBox* aBox, nsBoxSizeListener& aListener)=0;
     virtual void RemoveListener()=0;
-
+    virtual void SetAdjacent(nsBoxLayoutState& aState, nsBoxSizeList* aList)=0;
+    virtual nsBoxSizeList* GetAdjacent()=0;
 };
 
 // {AF0C1603-06C3-11d4-BA07-001083023C1E}
diff --git a/layout/xul/base/src/nsMonumentLayout.cpp b/layout/xul/base/src/nsMonumentLayout.cpp
index d3b17e165d1..4354bd8da16 100644
--- a/layout/xul/base/src/nsMonumentLayout.cpp
+++ b/layout/xul/base/src/nsMonumentLayout.cpp
@@ -179,16 +179,15 @@ nsMonumentIterator::GetNextObelisk(nsObeliskLayout** aObelisk, PRBool aSearchChi
 
 //------ nsInfoListNodeImpl ----
 
+nsBoxSizeListNodeImpl::~nsBoxSizeListNodeImpl()
+{
+
+}
+
 void
 nsBoxSizeListNodeImpl::Release(nsBoxLayoutState& aState)
 {
-   mRefCount--;
-   if (mRefCount == 0) {
-     Clear(aState);
-     if (mNext)
-       mNext->Release(aState);
-     delete this;
-   }
+  delete this;
 }
 
 void
@@ -201,18 +200,18 @@ nsBoxSizeListNodeImpl::Desecrate(nsBoxLayoutState& aState)
 void
 nsBoxSizeListNodeImpl::MarkDirty(nsBoxLayoutState& aState)
 {
-  mBox->MarkDirty(aState);
+  if (mBox)
+    mBox->MarkDirty(aState);
 }
 
 void nsBoxSizeListNodeImpl::SetNext(nsBoxLayoutState& aState, nsBoxSizeList* aNext)
 {
-  if (mNext) {
-    mNext->Release(aState);
-  }
-
   mNext = aNext;
-  if (mNext)
-    aNext->AddRef();
+}
+
+void nsBoxSizeListNodeImpl::SetAdjacent(nsBoxLayoutState& aState, nsBoxSizeList* aNext)
+{
+  mAdjacent = aNext;
 }
 
 void
@@ -223,6 +222,7 @@ nsBoxSizeListNodeImpl::Append(nsBoxLayoutState& aState, nsBoxSizeList* aChild)
 
 nsBoxSizeListNodeImpl::nsBoxSizeListNodeImpl(nsIBox* aBox):mNext(nsnull), 
                                                            mParent(nsnull), 
+                                                           mAdjacent(nsnull),
                                                            mBox(aBox),
                                                            mRefCount(0),
                                                            mIsSet(PR_FALSE)
@@ -239,7 +239,7 @@ nsBoxSizeListNodeImpl::GetAt(PRInt32 aIndex)
      if (count == aIndex)
         return node;
 
-     node = node->GetNext();
+     node = node->GetAdjacent();
      count++;
    }
 
@@ -272,15 +272,29 @@ nsBoxSizeListImpl::nsBoxSizeListImpl(nsIBox* aBox):nsBoxSizeListNodeImpl(aBox),
 {
 }
 
+nsBoxSizeListImpl::~nsBoxSizeListImpl()
+{
+}
+
 void
 nsBoxSizeListImpl::Release(nsBoxLayoutState& aState)
 {
-   if (mRefCount == 1) {
-     if (mListener)
-       mListener->WillBeDestroyed(mListenerBox, aState, *this);
-   }
+  if (mListener) {
+    mListener->WillBeDestroyed(mListenerBox, aState, *this);
+  }
 
-   nsBoxSizeListNodeImpl::Release(aState);
+  nsBoxSizeList* list = mFirst;
+  while(list)
+  {
+    nsBoxSizeList* toRelease = list;
+    list = list->GetNext();
+    toRelease->SetParent(nsnull);
+  }
+
+  if (mAdjacent)
+    mAdjacent->Release(aState);
+
+  delete this;
 }
 
 void
@@ -308,7 +322,6 @@ nsBoxSizeListImpl::Append(nsBoxLayoutState& aState, nsBoxSizeList* aChild)
 
   mLast = aChild;
   aChild->SetParent(this);
-  aChild->AddRef();
 }
 
 void
@@ -401,6 +414,9 @@ nsBoxSizeListNodeImpl::GetBoxSize(nsBoxLayoutState& aState, PRBool aIsHorizontal
   nscoord ascent = 0;
   nscoord flex = 0;
 
+  if (!mBox)
+    return size;
+
   mBox->GetPrefSize(aState, pref);
   mBox->GetMinSize(aState, min);
   mBox->GetMaxSize(aState, max);
@@ -502,8 +518,8 @@ nsMonumentLayout::GetOtherMonumentsAt(nsIBox* aBox, PRInt32 aIndexOfObelisk, nsB
        childBox = do_QueryInterface(childFrame);
      }
 
-     nsIBoxLayout* layout = nsnull;
-     childBox->GetLayoutManager(&layout);
+     nsCOMPtr<nsIBoxLayout> layout;
+     childBox->GetLayoutManager(getter_AddRefs(layout));
      
      // only all monuments
      nsCOMPtr<nsIMonument> monument = do_QueryInterface(layout, &rv);
@@ -556,7 +572,7 @@ nsMonumentLayout::GetMonumentsAt(nsIBox* aBox, PRInt32 aMonumentIndex, nsBoxSize
         *aList = list;
         return NS_OK;
      }
-     list = list->GetNext();
+     list = list->GetAdjacent();
      count++;
   }
 
@@ -607,7 +623,7 @@ nsMonumentLayout::GetMonumentList(nsIBox* aBox, nsBoxLayoutState& aState, nsBoxS
     if (*aList == nsnull) 
       *aList = last = newOne;
     else {
-      last->SetNext(aState, newOne);
+      last->SetAdjacent(aState, newOne);
       last = newOne;
     }
     child->GetNextBox(&child);
diff --git a/layout/xul/base/src/nsMonumentLayout.h b/layout/xul/base/src/nsMonumentLayout.h
index 0f08c2e0ea4..7c3bf379141 100644
--- a/layout/xul/base/src/nsMonumentLayout.h
+++ b/layout/xul/base/src/nsMonumentLayout.h
@@ -88,10 +88,15 @@ public:
     virtual PRBool IsSet() { return mIsSet; }
     virtual nsIBox* GetBox() { return mBox; }
 
+    virtual void SetAdjacent(nsBoxLayoutState& aState, nsBoxSizeList* aAdjacent);
+    virtual nsBoxSizeList* GetAdjacent() { return mAdjacent; }
+  
     nsBoxSizeListNodeImpl(nsIBox* aBox);
+    virtual ~nsBoxSizeListNodeImpl();
 
     nsBoxSizeList* mNext;
     nsBoxSizeList* mParent;
+    nsBoxSizeList* mAdjacent;
     nsIBox* mBox;
     PRInt32 mRefCount;
     PRBool mIsSet;
@@ -113,6 +118,7 @@ public:
     virtual void Release(nsBoxLayoutState& aState);
 
     nsBoxSizeListImpl(nsIBox* aBox);
+    virtual ~nsBoxSizeListImpl();
 
     nsBoxSizeList* mFirst;
     nsBoxSizeList* mLast;
diff --git a/layout/xul/base/src/nsTempleLayout.cpp b/layout/xul/base/src/nsTempleLayout.cpp
index 7bee9d11a41..bb4bd65cebc 100644
--- a/layout/xul/base/src/nsTempleLayout.cpp
+++ b/layout/xul/base/src/nsTempleLayout.cpp
@@ -73,52 +73,42 @@ nsTempleLayout::GetMonumentList(nsIBox* aBox, nsBoxLayoutState& aState, nsBoxSiz
      return NS_OK;
   }
 
-  *aList = nsnull;
-
   // run through our children.
   // ask each child for its monument list
   // append the list to our list
-  nsIBox* box = nsnull;
-  aBox->GetChildBox(&box);
+  nsIBox* firstChild = nsnull;
+  aBox->GetChildBox(&firstChild);
+
   nsBoxSizeList* current = nsnull;
   nsCOMPtr<nsIMonument> monument;
+  nsMonumentIterator it(firstChild);
 
-  nsMonumentIterator it(box);
-
+  nsIBox* box = nsnull;
   while(it.GetNextMonument(getter_AddRefs(monument))) {
 
       it.GetBox(&box);
 
-      if (!mMonuments) {
-          mMonuments = new nsBoxSizeListImpl(box);
-          mMonuments->AddRef();
-        }
-
       current = mMonuments;
       nsBoxSizeList* node = nsnull;
       monument->GetMonumentList(box, aState, &node);
 
-      if (node)
-          node->AddRef();
-
       while(node)
       {
+        if (!mMonuments) {
+          mMonuments = new nsBoxSizeListImpl(firstChild);
+          current = mMonuments;
+        }
+
         current->Append(aState, node);
-        node->Release(aState);
-
-        nsBoxSizeList* tmp = node->GetNext();
-        if (tmp)
-          tmp->AddRef();
-
-        node->SetNext(aState, nsnull);
-        node = tmp;
-
-        if (node && !current->GetNext()) {
+       
+        node = node->GetAdjacent();
+        
+        if (node && !current->GetAdjacent()) {
           nsBoxSizeList* newOne = new nsBoxSizeListImpl(box);
-          current->SetNext(aState, newOne);
+          current->SetAdjacent(aState, newOne);
           current = newOne;
         } else {
-          current = current->GetNext();
+          current = current->GetAdjacent();
         }
       }    
   }
@@ -225,10 +215,16 @@ nsTempleLayout::ChildrenRemoved(nsIBox* aBox, nsBoxLayoutState& aState, nsIBox*
 NS_IMETHODIMP
 nsTempleLayout::DesecrateMonuments(nsIBox* aBox, nsBoxLayoutState& aState)
 {
+  nsCOMPtr<nsIMonument> parent;
+  nsCOMPtr<nsIBox> parentBox;
+  GetParentMonument(aBox, parentBox, getter_AddRefs(parent));
+  if (parent)
+    parent->DesecrateMonuments(parentBox, aState);
+
   if (mMonuments) {
     nsBoxSizeList* tmp = mMonuments;
+    mMonuments->Release(aState);
     mMonuments = nsnull;
-    tmp->Release(aState);
   }
 
   return NS_OK;
diff --git a/layout/xul/base/src/nsTreeBoxObject.cpp b/layout/xul/base/src/nsTreeBoxObject.cpp
index 73522083462..1f94e9c10ef 100644
--- a/layout/xul/base/src/nsTreeBoxObject.cpp
+++ b/layout/xul/base/src/nsTreeBoxObject.cpp
@@ -33,7 +33,7 @@
 #include "nsIPresContext.h"
 #include "nsIFrame.h"
 
-//#define XULTREE
+#define XULTREE
 
 // XXX Hack
 #include "nsTreeOuterFrame.h"
diff --git a/layout/xul/base/src/nsTreeLayout.cpp b/layout/xul/base/src/nsTreeLayout.cpp
index cd2dd0c0beb..38b716cea33 100644
--- a/layout/xul/base/src/nsTreeLayout.cpp
+++ b/layout/xul/base/src/nsTreeLayout.cpp
@@ -94,7 +94,7 @@ nsTreeLayout::GetPrefSize(nsIBox* aBox, nsBoxLayoutState& aBoxLayoutState, nsSiz
     aSize.height = frame->GetRowCount() * rowheight;
     // Pad the height.
     nscoord y = frame->GetAvailableHeight();
-    if (y > 0 && rowheight > 0) {
+    if (aSize.height > y && y > 0 && rowheight > 0) {
       nscoord m = (aSize.height-y)%rowheight;
       nscoord remainder = m == 0 ? 0 : rowheight - m;
       aSize.height += remainder;
@@ -113,7 +113,7 @@ nsTreeLayout::GetMinSize(nsIBox* aBox, nsBoxLayoutState& aBoxLayoutState, nsSize
     aSize.height = frame->GetRowCount() * rowheight;
     // Pad the height.
     nscoord y = frame->GetAvailableHeight();
-    if (y > 0 && rowheight > 0) {
+    if (aSize.height > y && y > 0 && rowheight > 0) {
       nscoord m = (aSize.height-y)%rowheight;
       nscoord remainder = m == 0 ? 0 : rowheight - m;
       aSize.height += remainder;
@@ -132,7 +132,7 @@ nsTreeLayout::GetMaxSize(nsIBox* aBox, nsBoxLayoutState& aBoxLayoutState, nsSize
     aSize.height = frame->GetRowCount() * rowheight;
     // Pad the height.
     nscoord y = frame->GetAvailableHeight();
-    if (y > 0 && rowheight > 0) {
+    if (aSize.height > y && y > 0 && rowheight > 0) {
       nscoord m = (aSize.height-y)%rowheight;
       nscoord remainder = m == 0 ? 0 : rowheight - m;
       aSize.height += remainder;
diff --git a/layout/xul/base/src/nsXULTreeOuterGroupFrame.cpp b/layout/xul/base/src/nsXULTreeOuterGroupFrame.cpp
index 69c591b971d..f840063c682 100644
--- a/layout/xul/base/src/nsXULTreeOuterGroupFrame.cpp
+++ b/layout/xul/base/src/nsXULTreeOuterGroupFrame.cpp
@@ -25,6 +25,7 @@
 #include "nsCOMPtr.h"
 #include "nsXULTreeOuterGroupFrame.h"
 #include "nsXULAtoms.h"
+#include "nsHTMLAtoms.h"
 #include "nsIContent.h"
 #include "nsINameSpaceManager.h"
 #include "nsIScrollableFrame.h"
@@ -63,7 +64,7 @@ NS_NewXULTreeOuterGroupFrame(nsIPresShell* aPresShell, nsIFrame** aNewFrame, PRB
 // Constructor
 nsXULTreeOuterGroupFrame::nsXULTreeOuterGroupFrame(nsIPresShell* aPresShell, PRBool aIsRoot, nsIBoxLayout* aLayoutManager, PRBool aIsHorizontal)
 :nsXULTreeGroupFrame(aPresShell, aIsRoot, aLayoutManager, aIsHorizontal),
- mRowGroupInfo(nsnull), mRowHeight(TREE_LINE_HEIGHT), mCurrentIndex(0), mTwipIndex(0)
+ mRowGroupInfo(nsnull), mRowHeight(0), mCurrentIndex(0), mTwipIndex(0)
 {}
 
 // Destructor
@@ -124,6 +125,42 @@ nsXULTreeOuterGroupFrame::Init(nsIPresContext* aPresContext, nsIContent* aConten
 
 } // Init
 
+PRBool
+nsXULTreeOuterGroupFrame::IsFixedRowSize()
+{
+  nsCOMPtr<nsIContent> parent;
+  mContent->GetParent(*getter_AddRefs(parent));
+  nsAutoString rows;
+  parent->GetAttribute(kNameSpaceID_None, nsXULAtoms::rows, rows);
+  if (!rows.IsEmpty()) 
+    return PR_TRUE;
+  return PR_FALSE;
+}
+
+void
+nsXULTreeOuterGroupFrame::SetRowHeight(nscoord aRowHeight)
+{ 
+  if (mRowHeight == 0) { 
+    mRowHeight = aRowHeight;
+    nsCOMPtr<nsIContent> parent;
+    mContent->GetParent(*getter_AddRefs(parent));
+    nsAutoString rows;
+    parent->GetAttribute(kNameSpaceID_None, nsXULAtoms::rows, rows);
+    if (!rows.IsEmpty()) {
+      PRInt32 dummy;
+      PRInt32 count = rows.ToInteger(&dummy);
+      float t2p;
+      mPresContext->GetTwipsToPixels(&t2p);
+      PRInt32 rowHeight = NSTwipsToIntPixels(aRowHeight, t2p);
+      nsAutoString value;
+      value.AppendInt(rowHeight*count);
+      parent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::height, value, PR_FALSE);
+    }
+    nsBoxLayoutState state(mPresContext);
+    MarkDirtyChildren(state); 
+  } 
+}
+
 nscoord
 nsXULTreeOuterGroupFrame::GetYPosition()
 {
@@ -337,7 +374,7 @@ nsXULTreeOuterGroupFrame::InternalPositionChanged(PRBool aUp, PRInt32 aDelta)
     }
 
     nsBoxLayoutState state(mPresContext);
-    mFirstChild = mLastChild = nsnull;
+    ClearChildren(state);
     mFrames.DestroyFrames(mPresContext);
 
     nsCOMPtr<nsIContent> topRowContent;
@@ -715,19 +752,28 @@ nsXULTreeOuterGroupFrame::EnsureRowIsVisible(PRInt32 aRowIndex)
 {
   PRInt32 rows = GetAvailableHeight()/mRowHeight;
   PRInt32 bottomIndex = mCurrentIndex + rows - 1;
-  
+  if (IsFixedRowSize())
+    bottomIndex++;
+
   // if row is visible, ignore
   if (mCurrentIndex <= aRowIndex && aRowIndex <= bottomIndex)
     return;
 
-  // Try to center the new index.
-  PRInt32 newIndex = aRowIndex - rows/2;
-  if (newIndex < 0)
-    newIndex = 0;
-
+  PRInt32 newIndex = aRowIndex;
+  
   PRInt32 delta = mCurrentIndex > newIndex ? mCurrentIndex - newIndex : newIndex - mCurrentIndex;
-  PRInt32 up = newIndex < mCurrentIndex;
-  mCurrentIndex = newIndex;
+  PRBool up = newIndex < mCurrentIndex;
+  if (up)
+    mCurrentIndex = newIndex;
+  else {
+    // Scroll just enough to bring the newIndex into view.
+    PRInt32 adjustment = newIndex - rows;
+    if (!IsFixedRowSize())
+      adjustment++;
+    delta = adjustment - mCurrentIndex;
+    mCurrentIndex = adjustment;
+  }
+
   InternalPositionChanged(up, delta);
 
   // This change has to happen immediately.
@@ -742,7 +788,7 @@ nsXULTreeOuterGroupFrame::ScrollToIndex(PRInt32 aRowIndex)
 {
   PRInt32 newIndex = aRowIndex;
   PRInt32 delta = mCurrentIndex > newIndex ? mCurrentIndex - newIndex : newIndex - mCurrentIndex;
-  PRInt32 up = newIndex < mCurrentIndex;
+  PRBool up = newIndex < mCurrentIndex;
   mCurrentIndex = newIndex;
   InternalPositionChanged(up, delta);
 
diff --git a/layout/xul/base/src/nsXULTreeOuterGroupFrame.h b/layout/xul/base/src/nsXULTreeOuterGroupFrame.h
index 2fc598d785a..71ed5e4793c 100644
--- a/layout/xul/base/src/nsXULTreeOuterGroupFrame.h
+++ b/layout/xul/base/src/nsXULTreeOuterGroupFrame.h
@@ -95,14 +95,8 @@ public:
 
   void ClearRowGroupInfo() { if (mRowGroupInfo) mRowGroupInfo->Clear(); NeedsRecalc(); };
   
-  void SetRowHeight(PRInt32 aRowHeight) 
-  { 
-    if (mRowHeight != aRowHeight) { 
-      mRowHeight = aRowHeight;
-      nsBoxLayoutState state(mPresContext);
-      MarkDirtyChildren(state); 
-    } 
-  };
+  void SetRowHeight(PRInt32 aRowHeight);
+  PRBool IsFixedRowSize();
 
   nscoord GetYPosition();
   nscoord GetAvailableHeight();