diff --git a/mozilla/content/base/src/nsDocumentViewer.cpp b/mozilla/content/base/src/nsDocumentViewer.cpp
index b4c73356f56..06cbb966a8d 100644
--- a/mozilla/content/base/src/nsDocumentViewer.cpp
+++ b/mozilla/content/base/src/nsDocumentViewer.cpp
@@ -4723,7 +4723,7 @@ NS_IMETHODIMP DocumentViewerImpl::SetTextZoom(float aTextZoom)
   if (mDeviceContext) {
     mDeviceContext->SetTextZoom(aTextZoom);
     if (mPresContext) {
-      mPresContext->RemapStyleAndReflow();
+      mPresContext->ClearStyleDataAndReflow();
     }
   }
 
diff --git a/mozilla/content/base/src/nsStyleContext.cpp b/mozilla/content/base/src/nsStyleContext.cpp
index 50613a4117a..7e62deb7992 100644
--- a/mozilla/content/base/src/nsStyleContext.cpp
+++ b/mozilla/content/base/src/nsStyleContext.cpp
@@ -75,8 +75,6 @@ public:
   virtual PRBool    Equals(const nsIStyleContext* aOther) const;
   virtual PRBool    HasTextDecorations() { return mBits & NS_STYLE_HAS_TEXT_DECORATIONS; };
 
-  NS_IMETHOD RemapStyle(nsIPresContext* aPresContext, PRBool aRecurse = PR_TRUE);
-
   NS_IMETHOD GetBorderPaddingFor(nsStyleBorderPadding& aBorderPadding);
 
   NS_IMETHOD GetStyle(nsStyleStructID aSID, const nsStyleStruct** aStruct);
@@ -89,6 +87,8 @@ public:
   virtual const nsStyleStruct* GetStyleData(nsStyleStructID aSID);
   virtual nsStyleStruct* GetUniqueStyleData(nsIPresContext* aPresContext, const nsStyleStructID& aSID);
 
+  virtual nsresult ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule);
+
   virtual void ForceUnique(void);
   NS_IMETHOD  CalcStyleDifference(nsIStyleContext* aOther, PRInt32& aHint,PRBool aStopAtFirstDifference = PR_FALSE);
 
@@ -104,6 +104,8 @@ protected:
   void AppendChild(nsStyleContext* aChild);
   void RemoveChild(nsStyleContext* aChild);
 
+  void ApplyStyleFixups(nsIPresContext* aPresContext);
+
   nsStyleContext* mParent;
   nsStyleContext* mChild;
   nsStyleContext* mEmptyChild;
@@ -140,33 +142,7 @@ nsStyleContext::nsStyleContext(nsIStyleContext* aParent,
     mParent->AppendChild(this);
   }
 
-  // See if we have any text decorations.
-  // First see if our parent has text decorations.  If our parent does, then we inherit the bit.
-  if (mParent && mParent->HasTextDecorations())
-    mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
-  else {
-    // We might have defined a decoration.
-    const nsStyleTextReset* text = (const nsStyleTextReset*)GetStyleData(eStyleStruct_TextReset);
-    if (text->mTextDecoration != NS_STYLE_TEXT_DECORATION_NONE &&
-        text->mTextDecoration != NS_STYLE_TEXT_DECORATION_OVERRIDE_ALL)
-      mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
-  }
-
-  // Correct tables.
-  const nsStyleDisplay* disp = (const nsStyleDisplay*)GetStyleData(eStyleStruct_Display);
-  if (disp->mDisplay == NS_STYLE_DISPLAY_TABLE) {
-    // -moz-center and -moz-right are used for HTML's alignment
-    // This is covering the <div align="right"><table>...</table></div> case.
-    // In this case, we don't want to inherit the text alignment into the table.
-    const nsStyleText* text = (const nsStyleText*)GetStyleData(eStyleStruct_Text);
-    
-    if (text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
-        text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)
-    {
-      nsStyleText* uniqueText = (nsStyleText*)GetUniqueStyleData(aPresContext, eStyleStruct_Text);
-      uniqueText->mTextAlign = NS_STYLE_TEXT_ALIGN_DEFAULT;
-    }
-  }
+  ApplyStyleFixups(aPresContext);
 }
 
 nsStyleContext::~nsStyleContext()
@@ -545,30 +521,60 @@ nsStyleContext::SetStyle(nsStyleStructID aSID, const nsStyleStruct& aStruct)
   return result;
 }
 
-NS_IMETHODIMP
-nsStyleContext::RemapStyle(nsIPresContext* aPresContext, PRBool aRecurse)
+void
+nsStyleContext::ApplyStyleFixups(nsIPresContext* aPresContext)
 {
-#if 0 // Commenting out until we figure out why this crashes only on opt builds.
-  // First we need to clear out all of our style data.
-  if (mCachedStyleData.mResetData || mCachedStyleData.mInheritedData)
-    mCachedStyleData.Destroy(mBits, aPresContext);
+  // See if we have any text decorations.
+  // First see if our parent has text decorations.  If our parent does, then we inherit the bit.
+  if (mParent && mParent->HasTextDecorations())
+    mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
+  else {
+    // We might have defined a decoration.
+    const nsStyleTextReset* text = (const nsStyleTextReset*)GetStyleData(eStyleStruct_TextReset);
+    if (text->mTextDecoration != NS_STYLE_TEXT_DECORATION_NONE &&
+        text->mTextDecoration != NS_STYLE_TEXT_DECORATION_OVERRIDE_ALL)
+      mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
+  }
 
-  mBits &= ~NS_STYLE_INHERIT_MASK;  // Clear out all data that indicates we should look for
-                                    // style data in our parent.
+  // Correct tables.
+  const nsStyleDisplay* disp = (const nsStyleDisplay*)GetStyleData(eStyleStruct_Display);
+  if (disp->mDisplay == NS_STYLE_DISPLAY_TABLE) {
+    // -moz-center and -moz-right are used for HTML's alignment
+    // This is covering the <div align="right"><table>...</table></div> case.
+    // In this case, we don't want to inherit the text alignment into the table.
+    const nsStyleText* text = (const nsStyleText*)GetStyleData(eStyleStruct_Text);
+    
+    if (text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
+        text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)
+    {
+      nsStyleText* uniqueText = (nsStyleText*)GetUniqueStyleData(aPresContext, eStyleStruct_Text);
+      uniqueText->mTextAlign = NS_STYLE_TEXT_ALIGN_DEFAULT;
+    }
+  }
+}
 
-  // Now we need to ensure that any cached data along the path from our
-  // rule node back to the root is cleared out.
-  mRuleNode->ClearPath();
+nsresult
+nsStyleContext::ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule)
+{
+  PRBool matched = PR_TRUE;
+  if (aRule)
+    mRuleNode->PathContainsRule(aRule, &matched);
+  
+  if (matched) {
+    // First we need to clear out all of our style data.
+    if (mCachedStyleData.mResetData || mCachedStyleData.mInheritedData)
+      mCachedStyleData.Destroy(mBits, aPresContext);
 
-  // Now do the same for all of our children, but only if the recurse boolean
-  // is set.
-  if (!aRecurse)
-    return NS_OK;
+    mBits = 0; // Clear all bits.
+    aRule = nsnull;
+  }
+
+  ApplyStyleFixups(aPresContext);
 
   if (mChild) {
     nsStyleContext* child = mChild;
     do {
-      child->RemapStyle(aPresContext);
+      child->ClearStyleData(aPresContext, aRule);
       child = child->mNextSibling;
     } while (mChild != child);
   }
@@ -576,11 +582,11 @@ nsStyleContext::RemapStyle(nsIPresContext* aPresContext, PRBool aRecurse)
   if (mEmptyChild) {
     nsStyleContext* child = mEmptyChild;
     do {
-      child->RemapStyle(aPresContext);
+      child->ClearStyleData(aPresContext, aRule);
       child = child->mNextSibling;
     } while (mEmptyChild != child);
   }
-#endif
+
   return NS_OK;
 }
 
diff --git a/mozilla/content/base/src/nsStyleSet.cpp b/mozilla/content/base/src/nsStyleSet.cpp
index 2ed87c83f2a..44921c48b5e 100644
--- a/mozilla/content/base/src/nsStyleSet.cpp
+++ b/mozilla/content/base/src/nsStyleSet.cpp
@@ -115,6 +115,7 @@ public:
   NS_IMETHOD Shutdown();
 
   virtual nsresult GetRuleTree(nsIRuleNode** aResult);
+  virtual nsresult ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule, nsIStyleContext* aContext);
 
   NS_IMETHOD ReParentStyleContext(nsIPresContext* aPresContext,
                                   nsIStyleContext* aStyleContext, 
@@ -985,6 +986,53 @@ StyleSetImpl::GetRuleTree(nsIRuleNode** aResult)
   return NS_OK;
 }
 
+nsresult
+StyleSetImpl::ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule, nsIStyleContext* aContext)
+{
+  // XXXdwh.  If we're willing to *really* optimize this
+  // invalidation, we could only invalidate the struct data
+  // that actually changed.  For example, if someone changes
+  // style.left, we really only need to blow away cached
+  // data in the position struct.
+  if (aContext) {
+    nsCOMPtr<nsIRuleNode> ruleNode;
+    aContext->GetRuleNode(getter_AddRefs(ruleNode));
+    ruleNode->ClearCachedData(aRule); 
+
+    // We don't need to mess with the style tree in this case, since the act of 
+    // changing inline style attributes automatically causes re-resolution to a new style context
+    // (with new descendant style contexts as well).
+  }
+  else {
+    // XXXdwh This is not terribly fast, but fortunately this case is rare (and often a full tree
+    // invalidation anyway).  Improving performance here would involve a footprint
+    // increase.  Mappings from rule nodes to their associated style contexts as well as
+    // mappings from rules to their associated rule nodes would enable us to avoid the two
+    // tree walks that occur here.
+
+    // Crawl the entire rule tree and blow away all data for rule nodes (and their descendants)
+    // that have the given rule.
+    if (mRuleTree)
+      mRuleTree->ClearCachedDataInSubtree(aRule);
+
+    // We need to crawl the entire style context tree, and for each style context we need 
+    // to see if the specified rule is matched.  If so, that context and all its descendant
+    // contexts must have their data wiped.
+    nsCOMPtr<nsIPresShell> shell;
+    aPresContext->GetShell(getter_AddRefs(shell));
+    nsIFrame* rootFrame;
+    shell->GetRootFrame(&rootFrame);
+    if (rootFrame) {
+      nsCOMPtr<nsIStyleContext> rootContext;
+      rootFrame->GetStyleContext(getter_AddRefs(rootContext));
+      if (rootContext)
+        rootContext->ClearStyleData(aPresContext, aRule);
+    }
+  }
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 StyleSetImpl::ReParentStyleContext(nsIPresContext* aPresContext,
                                    nsIStyleContext* aStyleContext, 
diff --git a/mozilla/content/html/style/public/nsIRuleNode.h b/mozilla/content/html/style/public/nsIRuleNode.h
index 9cebc751989..475990b9107 100644
--- a/mozilla/content/html/style/public/nsIRuleNode.h
+++ b/mozilla/content/html/style/public/nsIRuleNode.h
@@ -299,7 +299,8 @@ public:
 
   NS_IMETHOD GetPresContext(nsIPresContext** aResult)=0;
 
-  NS_IMETHOD ClearPath()=0;
+  NS_IMETHOD PathContainsRule(nsIStyleRule* aRule, PRBool* aMatched) = 0;
+
   NS_IMETHOD ClearCachedData(nsIStyleRule* aRule)=0;
   NS_IMETHOD ClearCachedDataInSubtree(nsIStyleRule* aRule)=0;
   
diff --git a/mozilla/content/html/style/src/nsRuleNode.cpp b/mozilla/content/html/style/src/nsRuleNode.cpp
index 78d15bb7647..9ff44e63953 100644
--- a/mozilla/content/html/style/src/nsRuleNode.cpp
+++ b/mozilla/content/html/style/src/nsRuleNode.cpp
@@ -412,24 +412,18 @@ nsRuleNode::GetRule(nsIStyleRule** aResult)
   return NS_OK;
 }
 
-PRBool PR_CALLBACK ClearCachedDataHelper(nsHashKey* aKey, void* aData, void* aClosure)
-{
-  nsRuleNode* ruleNode = (nsRuleNode*)aData;
-  ruleNode->ClearPath();
-  return PR_TRUE;
-}
-
 NS_IMETHODIMP
-nsRuleNode::ClearPath()
+nsRuleNode::PathContainsRule(nsIStyleRule* aRule, PRBool* aMatched)
 {
-  // Any children must not be allowed to obtain cached data from parents.  We must
-  // clear any bits in descendants that indicate inheritance.
-  mInheritBits &= ~NS_STYLE_INHERIT_MASK;
-  if (mStyleData.mResetData || mStyleData.mInheritedData)
-    mStyleData.Destroy(0, mPresContext);
-
-  if (mChildren)
-    mChildren->Enumerate(ClearCachedDataHelper);
+  *aMatched = PR_FALSE;
+  nsRuleNode* ruleDest = this;
+  while (ruleDest) {
+    if (ruleDest->mRule == aRule) {
+      *aMatched = PR_TRUE;
+      break;
+    }
+    ruleDest = ruleDest->mParent;
+  }
 
   return NS_OK;
 }
@@ -446,7 +440,10 @@ nsRuleNode::ClearCachedData(nsIStyleRule* aRule)
 
   if (ruleDest) {
     // The rule was contained along our branch.  We need to blow away
-    // all cached data along this path.
+    // all cached data along this path.  Note that, because of the definition
+    // of inline style, all nodes along this path must have exactly one child.  This
+    // is not a bushy subtree, and so we know that by clearing this path, we've
+    // invalidated everything that we need to.
     nsRuleNode* curr = this;
     while (curr) {
       curr->mNoneBits &= ~NS_STYLE_INHERIT_MASK;
@@ -475,12 +472,13 @@ PRBool PR_CALLBACK ClearCachedDataInSubtreeHelper(nsHashKey* aKey, void* aData,
 NS_IMETHODIMP
 nsRuleNode::ClearCachedDataInSubtree(nsIStyleRule* aRule)
 {
-  if (mRule == aRule) {
+  if (aRule == nsnull || mRule == aRule) {
     // We have a match.  Blow away all data stored at this node.
     if (mStyleData.mResetData || mStyleData.mInheritedData)
       mStyleData.Destroy(0, mPresContext);
     mNoneBits &= ~NS_STYLE_INHERIT_MASK;
-    mInheritBits &= ~NS_STYLE_INHERIT_MASK;  // XXXdwh need to clear all data in descendants!
+    mInheritBits &= ~NS_STYLE_INHERIT_MASK;
+    aRule = nsnull;
   }
 
   if (mChildren)
diff --git a/mozilla/content/html/style/src/nsRuleNode.h b/mozilla/content/html/style/src/nsRuleNode.h
index 815765f83e6..46f85b8c75a 100644
--- a/mozilla/content/html/style/src/nsRuleNode.h
+++ b/mozilla/content/html/style/src/nsRuleNode.h
@@ -240,10 +240,10 @@ public:
   NS_IMETHOD GetParent(nsIRuleNode** aResult);
   NS_IMETHOD IsRoot(PRBool* aResult);
   NS_IMETHOD GetRule(nsIStyleRule** aResult);
-  NS_IMETHOD ClearPath();
   NS_IMETHOD ClearCachedData(nsIStyleRule* aRule);
   NS_IMETHOD ClearCachedDataInSubtree(nsIStyleRule* aRule);
   NS_IMETHOD GetPresContext(nsIPresContext** aResult);
+  NS_IMETHOD PathContainsRule(nsIStyleRule* aRule, PRBool* aMatched);
   const nsStyleStruct* GetStyleData(nsStyleStructID aSID, 
                                     nsIStyleContext* aContext);
 };
diff --git a/mozilla/layout/base/nsCSSFrameConstructor.cpp b/mozilla/layout/base/nsCSSFrameConstructor.cpp
index a6425c2dc90..40deca6f626 100644
--- a/mozilla/layout/base/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/base/nsCSSFrameConstructor.cpp
@@ -10020,25 +10020,9 @@ nsCSSFrameConstructor::AttributeChanged(nsIPresContext* aPresContext,
   }
   else if (restyle) {
     if (inlineStyle) {
-      if (styleContext) {
-        nsCOMPtr<nsIRuleNode> ruleNode;
-        styleContext->GetRuleNode(getter_AddRefs(ruleNode));
-        ruleNode->ClearCachedData(rule); // XXXdwh.  If we're willing to *really* special case
-                                         // inline style, we could only invalidate the struct data
-                                         // that actually changed.  For example, if someone changes
-                                         // style.left, we really only need to blow away cached
-                                         // data in the position struct.
-      }
-      else {
-        // Ok, our only option left is to just crawl the entire rule
-        // tree and blow away the data that way.
-        nsCOMPtr<nsIStyleSet> set;
-        shell->GetStyleSet(getter_AddRefs(set));
-        nsCOMPtr<nsIRuleNode> rootNode;
-        set->GetRuleTree(getter_AddRefs(rootNode));
-        if (rootNode)
-          rootNode->ClearCachedDataInSubtree(rule);
-      }
+      nsCOMPtr<nsIStyleSet> set;
+      shell->GetStyleSet(getter_AddRefs(set));
+      set->ClearStyleData(aPresContext, rule, styleContext);
     }
 
     // If there is no frame then there is no point in re-styling it,
@@ -10164,10 +10148,9 @@ nsCSSFrameConstructor::StyleRuleChanged(nsIPresContext* aPresContext,
   }
 
   if (restyle) {
-    nsIStyleContext* sc;
-    frame->GetStyleContext(&sc);
-    sc->RemapStyle(aPresContext);
-    NS_RELEASE(sc);
+    nsCOMPtr<nsIStyleSet> set;
+    shell->GetStyleSet(getter_AddRefs(set));
+    set->ClearStyleData(aPresContext, aStyleRule, nsnull);
   }
 
   if (reframe) {
diff --git a/mozilla/layout/base/nsDocumentViewer.cpp b/mozilla/layout/base/nsDocumentViewer.cpp
index b4c73356f56..06cbb966a8d 100644
--- a/mozilla/layout/base/nsDocumentViewer.cpp
+++ b/mozilla/layout/base/nsDocumentViewer.cpp
@@ -4723,7 +4723,7 @@ NS_IMETHODIMP DocumentViewerImpl::SetTextZoom(float aTextZoom)
   if (mDeviceContext) {
     mDeviceContext->SetTextZoom(aTextZoom);
     if (mPresContext) {
-      mPresContext->RemapStyleAndReflow();
+      mPresContext->ClearStyleDataAndReflow();
     }
   }
 
diff --git a/mozilla/layout/base/nsFrameManager.cpp b/mozilla/layout/base/nsFrameManager.cpp
index bf82b036e9e..c82f7702de4 100644
--- a/mozilla/layout/base/nsFrameManager.cpp
+++ b/mozilla/layout/base/nsFrameManager.cpp
@@ -1700,7 +1700,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         }
       }
       else {
-        oldContext->RemapStyle(aPresContext, PR_FALSE);
+        // XXXdwh figure this out.
+        // oldContext->RemapStyle(aPresContext, PR_FALSE);
         if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
             HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
           aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1735,7 +1736,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
               }
             }
             else {
-              oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
+              // XXXdwh figure this out.
+              // oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
               if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
                   HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
                 aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1769,7 +1771,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         NS_IF_RELEASE(pseudoTag);
         if (undisplayedContext) {
           if (undisplayedContext == undisplayed->mStyle) {
-            undisplayedContext->RemapStyle(aPresContext);
+            // XXXdwh figure this out.
+            // undisplayedContext->RemapStyle(aPresContext);
           }
           const nsStyleDisplay* display = 
                 (const nsStyleDisplay*)undisplayedContext->GetStyleData(eStyleStruct_Display);
@@ -1912,7 +1915,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         }
       }
       else {
-        oldContext->RemapStyle(aPresContext, PR_FALSE);
+        // XXXdwh figure this out.
+        // oldContext->RemapStyle(aPresContext, PR_FALSE);
         if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
             HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
           aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1947,7 +1951,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
               }
             }
             else {
-              oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
+              // XXXdwh figure this out.
+              // oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
               if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
                   HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
                 aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1981,7 +1986,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         NS_IF_RELEASE(pseudoTag);
         if (undisplayedContext) {
           if (undisplayedContext == undisplayed->mStyle) {
-            undisplayedContext->RemapStyle(aPresContext);
+            // XXXdwh figure this out.
+            // undisplayedContext->RemapStyle(aPresContext);
           }
           const nsStyleDisplay* display = 
                 (const nsStyleDisplay*)undisplayedContext->GetStyleData(eStyleStruct_Display);
diff --git a/mozilla/layout/base/nsPresContext.cpp b/mozilla/layout/base/nsPresContext.cpp
index edd6a37c41b..afa2b2faf3e 100644
--- a/mozilla/layout/base/nsPresContext.cpp
+++ b/mozilla/layout/base/nsPresContext.cpp
@@ -25,6 +25,7 @@
 #include "nsIPresShell.h"
 #include "nsIPref.h"
 #include "nsILinkHandler.h"
+#include "nsIDocShellTreeItem.h"
 #include "nsIStyleSet.h"
 #include "nsFrameImageLoader.h"
 #include "nsIFrameManager.h"
@@ -399,21 +400,20 @@ nsPresContext::GetCachedBoolPref(PRUint32 prefType, PRBool &aValue)
 }
 
 NS_IMETHODIMP
-nsPresContext::RemapStyleAndReflow()
+nsPresContext::ClearStyleDataAndReflow()
 {
   if (mShell) {
+    // Clear out all our style data.
+    nsCOMPtr<nsIStyleSet> set;
+    mShell->GetStyleSet(getter_AddRefs(set));
+    set->ClearStyleData(this, nsnull, nsnull);
+
     // Have the root frame's style context remap its style based on the
     // user preferences
     nsIFrame* rootFrame;
 
     mShell->GetRootFrame(&rootFrame);
     if (rootFrame) {
-      nsIStyleContext*  rootStyleContext;
-
-      rootFrame->GetStyleContext(&rootStyleContext);
-      rootStyleContext->RemapStyle(this);
-      NS_RELEASE(rootStyleContext);
-  
       // boxes know how to coelesce style changes. So if our root frame is a box
       // then tell it to handle it. If its a block we are stuck with a full top to bottom
       // reflow. -EDV
@@ -440,6 +440,14 @@ nsPresContext::RemapStyleAndReflow()
 void
 nsPresContext::PreferenceChanged(const char* aPrefName)
 {
+  nsCOMPtr<nsIDocShellTreeItem> docShell(do_QueryInterface(mContainer));
+  if (docShell) {
+    PRInt32 docShellType;
+    docShell->GetItemType(&docShellType);
+    if (nsIDocShellTreeItem::typeChrome == docShellType)
+      return;
+  }
+
   // XXX for WM_FONTCHANGE messages, only flush the font cache (bug=89493)
  //     because nsObjectFrame can't handle a reframe at this time              
   if (strcmp(aPrefName,"font.internaluseonly.changed") == 0) {
@@ -459,7 +467,7 @@ nsPresContext::PreferenceChanged(const char* aPrefName)
 
   if (mDeviceContext) {
     mDeviceContext->FlushFontCache();
-    RemapStyleAndReflow();
+    ClearStyleDataAndReflow();
   }
 }
 
@@ -1551,7 +1559,7 @@ NS_IMETHODIMP   nsPresContext::SetBidi(PRUint32 aSource, PRBool aForceReflow)
     SetVisualMode(IsVisualCharset(mCharset) );
   }
   if (mShell && aForceReflow) {
-    RemapStyleAndReflow();
+    ClearStyleDataAndReflow();
   }
   return NS_OK;
 }
diff --git a/mozilla/layout/base/nsPresContext.h b/mozilla/layout/base/nsPresContext.h
index 65a177a966d..42284a95d06 100644
--- a/mozilla/layout/base/nsPresContext.h
+++ b/mozilla/layout/base/nsPresContext.h
@@ -158,9 +158,9 @@ public:
   NS_IMETHOD GetMedium(nsIAtom** aMediumResult) = 0;
 
   /**
-   * Remap style from the root frame downwards, and reflow.
+   * Clear style data from the root frame downwards, and reflow.
    */
-  NS_IMETHOD RemapStyleAndReflow(void) = 0;
+  NS_IMETHOD ClearStyleDataAndReflow(void) = 0;
 
   /**
    * Resolve style for the given piece of content that will be a child
diff --git a/mozilla/layout/base/nsPresShell.cpp b/mozilla/layout/base/nsPresShell.cpp
index cb062f20866..3499d301728 100644
--- a/mozilla/layout/base/nsPresShell.cpp
+++ b/mozilla/layout/base/nsPresShell.cpp
@@ -5281,11 +5281,7 @@ PresShell::BidiStyleChangeReflow()
   mFrameManager->GetRootFrame(&rootFrame);
 
   if (rootFrame) {
-    nsIStyleContext*  rootStyleContext;
-    rootFrame->GetStyleContext(&rootStyleContext);
-    rootStyleContext->RemapStyle(mPresContext.get() );
-    NS_RELEASE(rootStyleContext);
-
+    mStyleSet->ClearStyleData(mPresContext, nsnull, nsnull);
     ReconstructFrames();
   }
   return NS_OK;
diff --git a/mozilla/layout/base/public/nsIPresContext.h b/mozilla/layout/base/public/nsIPresContext.h
index 65a177a966d..42284a95d06 100644
--- a/mozilla/layout/base/public/nsIPresContext.h
+++ b/mozilla/layout/base/public/nsIPresContext.h
@@ -158,9 +158,9 @@ public:
   NS_IMETHOD GetMedium(nsIAtom** aMediumResult) = 0;
 
   /**
-   * Remap style from the root frame downwards, and reflow.
+   * Clear style data from the root frame downwards, and reflow.
    */
-  NS_IMETHOD RemapStyleAndReflow(void) = 0;
+  NS_IMETHOD ClearStyleDataAndReflow(void) = 0;
 
   /**
    * Resolve style for the given piece of content that will be a child
diff --git a/mozilla/layout/base/public/nsIStyleContext.h b/mozilla/layout/base/public/nsIStyleContext.h
index 476d3cfac73..2d1d8bd25f2 100644
--- a/mozilla/layout/base/public/nsIStyleContext.h
+++ b/mozilla/layout/base/public/nsIStyleContext.h
@@ -101,10 +101,12 @@ public:
   // display.  Don't add support for new structs or use this method without careful consideration! -dwh
   virtual nsStyleStruct* GetUniqueStyleData(nsIPresContext* aPresContext, const nsStyleStructID& aSID) = 0;
 
+  // Used to clear away the style data for a given style context if it matches the specified |aRule|.
+  // If |aRule| is null, then the style data is always blown away.
+  virtual nsresult ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule) = 0;
+ 
   // call this to prevent context from getting shared
   virtual void  ForceUnique(void) = 0;
-
-  NS_IMETHOD RemapStyle(nsIPresContext* aPresContext, PRBool aRecurse = PR_TRUE) = 0;
 };
 
 
diff --git a/mozilla/layout/base/public/nsIStyleSet.h b/mozilla/layout/base/public/nsIStyleSet.h
index 6a01a01300b..9a76e1a0efd 100644
--- a/mozilla/layout/base/public/nsIStyleSet.h
+++ b/mozilla/layout/base/public/nsIStyleSet.h
@@ -82,6 +82,17 @@ public:
   
   virtual nsresult GetRuleTree(nsIRuleNode** aResult) = 0;
 
+  // ClearCachedStyleData is used to invalidate portions of both the style context tree
+  // and rule tree without destroying the actual nodes in the two trees.  |aRule| provides
+  // a hint as to which rule has changed, and all subtree data pruning will occur rooted
+  // only on style contexts and rule nodes that use that rule.  If the rule is null, then
+  // it is assumed that both trees are to be entirely wiped.
+  //
+  // |aContext| provides an additional hint that a specific style context has changed, and
+  // that the entire rule tree need not be searched for occurrences of |aRule|.  It is
+  // only specified in the inline style case, i.e., when the inline style attribute changes.
+  virtual nsresult ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule, nsIStyleContext* aContext) = 0;
+
   // enable / disable the Quirk style sheet: 
   // returns NS_FAILURE if none is found, otherwise NS_OK
   NS_IMETHOD EnableQuirkStyleSheet(PRBool aEnable) = 0;
diff --git a/mozilla/layout/base/public/nsPresContext.h b/mozilla/layout/base/public/nsPresContext.h
index 65a177a966d..42284a95d06 100644
--- a/mozilla/layout/base/public/nsPresContext.h
+++ b/mozilla/layout/base/public/nsPresContext.h
@@ -158,9 +158,9 @@ public:
   NS_IMETHOD GetMedium(nsIAtom** aMediumResult) = 0;
 
   /**
-   * Remap style from the root frame downwards, and reflow.
+   * Clear style data from the root frame downwards, and reflow.
    */
-  NS_IMETHOD RemapStyleAndReflow(void) = 0;
+  NS_IMETHOD ClearStyleDataAndReflow(void) = 0;
 
   /**
    * Resolve style for the given piece of content that will be a child
diff --git a/mozilla/layout/base/src/nsPresContext.cpp b/mozilla/layout/base/src/nsPresContext.cpp
index edd6a37c41b..afa2b2faf3e 100644
--- a/mozilla/layout/base/src/nsPresContext.cpp
+++ b/mozilla/layout/base/src/nsPresContext.cpp
@@ -25,6 +25,7 @@
 #include "nsIPresShell.h"
 #include "nsIPref.h"
 #include "nsILinkHandler.h"
+#include "nsIDocShellTreeItem.h"
 #include "nsIStyleSet.h"
 #include "nsFrameImageLoader.h"
 #include "nsIFrameManager.h"
@@ -399,21 +400,20 @@ nsPresContext::GetCachedBoolPref(PRUint32 prefType, PRBool &aValue)
 }
 
 NS_IMETHODIMP
-nsPresContext::RemapStyleAndReflow()
+nsPresContext::ClearStyleDataAndReflow()
 {
   if (mShell) {
+    // Clear out all our style data.
+    nsCOMPtr<nsIStyleSet> set;
+    mShell->GetStyleSet(getter_AddRefs(set));
+    set->ClearStyleData(this, nsnull, nsnull);
+
     // Have the root frame's style context remap its style based on the
     // user preferences
     nsIFrame* rootFrame;
 
     mShell->GetRootFrame(&rootFrame);
     if (rootFrame) {
-      nsIStyleContext*  rootStyleContext;
-
-      rootFrame->GetStyleContext(&rootStyleContext);
-      rootStyleContext->RemapStyle(this);
-      NS_RELEASE(rootStyleContext);
-  
       // boxes know how to coelesce style changes. So if our root frame is a box
       // then tell it to handle it. If its a block we are stuck with a full top to bottom
       // reflow. -EDV
@@ -440,6 +440,14 @@ nsPresContext::RemapStyleAndReflow()
 void
 nsPresContext::PreferenceChanged(const char* aPrefName)
 {
+  nsCOMPtr<nsIDocShellTreeItem> docShell(do_QueryInterface(mContainer));
+  if (docShell) {
+    PRInt32 docShellType;
+    docShell->GetItemType(&docShellType);
+    if (nsIDocShellTreeItem::typeChrome == docShellType)
+      return;
+  }
+
   // XXX for WM_FONTCHANGE messages, only flush the font cache (bug=89493)
  //     because nsObjectFrame can't handle a reframe at this time              
   if (strcmp(aPrefName,"font.internaluseonly.changed") == 0) {
@@ -459,7 +467,7 @@ nsPresContext::PreferenceChanged(const char* aPrefName)
 
   if (mDeviceContext) {
     mDeviceContext->FlushFontCache();
-    RemapStyleAndReflow();
+    ClearStyleDataAndReflow();
   }
 }
 
@@ -1551,7 +1559,7 @@ NS_IMETHODIMP   nsPresContext::SetBidi(PRUint32 aSource, PRBool aForceReflow)
     SetVisualMode(IsVisualCharset(mCharset) );
   }
   if (mShell && aForceReflow) {
-    RemapStyleAndReflow();
+    ClearStyleDataAndReflow();
   }
   return NS_OK;
 }
diff --git a/mozilla/layout/base/src/nsPresContext.h b/mozilla/layout/base/src/nsPresContext.h
index c6e38a15eca..afb295d46c7 100644
--- a/mozilla/layout/base/src/nsPresContext.h
+++ b/mozilla/layout/base/src/nsPresContext.h
@@ -63,7 +63,7 @@ public:
   NS_IMETHOD GetLookAndFeel(nsILookAndFeel** aLookAndFeel);
   NS_IMETHOD GetBaseURL(nsIURI** aURLResult);
   NS_IMETHOD GetMedium(nsIAtom** aMediumResult) = 0;
-  NS_IMETHOD RemapStyleAndReflow(void);
+  NS_IMETHOD ClearStyleDataAndReflow(void);
   NS_IMETHOD ResolveStyleContextFor(nsIContent* aContent,
                                     nsIStyleContext* aParentContext,
                                     PRBool aForceUnique,
diff --git a/mozilla/layout/html/base/src/nsFrameManager.cpp b/mozilla/layout/html/base/src/nsFrameManager.cpp
index bf82b036e9e..c82f7702de4 100644
--- a/mozilla/layout/html/base/src/nsFrameManager.cpp
+++ b/mozilla/layout/html/base/src/nsFrameManager.cpp
@@ -1700,7 +1700,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         }
       }
       else {
-        oldContext->RemapStyle(aPresContext, PR_FALSE);
+        // XXXdwh figure this out.
+        // oldContext->RemapStyle(aPresContext, PR_FALSE);
         if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
             HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
           aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1735,7 +1736,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
               }
             }
             else {
-              oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
+              // XXXdwh figure this out.
+              // oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
               if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
                   HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
                 aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1769,7 +1771,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         NS_IF_RELEASE(pseudoTag);
         if (undisplayedContext) {
           if (undisplayedContext == undisplayed->mStyle) {
-            undisplayedContext->RemapStyle(aPresContext);
+            // XXXdwh figure this out.
+            // undisplayedContext->RemapStyle(aPresContext);
           }
           const nsStyleDisplay* display = 
                 (const nsStyleDisplay*)undisplayedContext->GetStyleData(eStyleStruct_Display);
@@ -1912,7 +1915,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         }
       }
       else {
-        oldContext->RemapStyle(aPresContext, PR_FALSE);
+        // XXXdwh figure this out.
+        // oldContext->RemapStyle(aPresContext, PR_FALSE);
         if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
             HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
           aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1947,7 +1951,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
               }
             }
             else {
-              oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
+              // XXXdwh figure this out.
+              // oldExtraContext->RemapStyle(aPresContext, PR_FALSE);
               if (aAttribute && (aMinChange < NS_STYLE_HINT_REFLOW) &&
                   HasAttributeContent(oldContext, aAttrNameSpaceID, aAttribute)) {
                 aChangeList.AppendChange(aFrame, content, NS_STYLE_HINT_REFLOW);
@@ -1981,7 +1986,8 @@ FrameManager::ReResolveStyleContext(nsIPresContext* aPresContext,
         NS_IF_RELEASE(pseudoTag);
         if (undisplayedContext) {
           if (undisplayedContext == undisplayed->mStyle) {
-            undisplayedContext->RemapStyle(aPresContext);
+            // XXXdwh figure this out.
+            // undisplayedContext->RemapStyle(aPresContext);
           }
           const nsStyleDisplay* display = 
                 (const nsStyleDisplay*)undisplayedContext->GetStyleData(eStyleStruct_Display);
diff --git a/mozilla/layout/html/base/src/nsPresShell.cpp b/mozilla/layout/html/base/src/nsPresShell.cpp
index cb062f20866..3499d301728 100644
--- a/mozilla/layout/html/base/src/nsPresShell.cpp
+++ b/mozilla/layout/html/base/src/nsPresShell.cpp
@@ -5281,11 +5281,7 @@ PresShell::BidiStyleChangeReflow()
   mFrameManager->GetRootFrame(&rootFrame);
 
   if (rootFrame) {
-    nsIStyleContext*  rootStyleContext;
-    rootFrame->GetStyleContext(&rootStyleContext);
-    rootStyleContext->RemapStyle(mPresContext.get() );
-    NS_RELEASE(rootStyleContext);
-
+    mStyleSet->ClearStyleData(mPresContext, nsnull, nsnull);
     ReconstructFrames();
   }
   return NS_OK;
diff --git a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
index a6425c2dc90..40deca6f626 100644
--- a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -10020,25 +10020,9 @@ nsCSSFrameConstructor::AttributeChanged(nsIPresContext* aPresContext,
   }
   else if (restyle) {
     if (inlineStyle) {
-      if (styleContext) {
-        nsCOMPtr<nsIRuleNode> ruleNode;
-        styleContext->GetRuleNode(getter_AddRefs(ruleNode));
-        ruleNode->ClearCachedData(rule); // XXXdwh.  If we're willing to *really* special case
-                                         // inline style, we could only invalidate the struct data
-                                         // that actually changed.  For example, if someone changes
-                                         // style.left, we really only need to blow away cached
-                                         // data in the position struct.
-      }
-      else {
-        // Ok, our only option left is to just crawl the entire rule
-        // tree and blow away the data that way.
-        nsCOMPtr<nsIStyleSet> set;
-        shell->GetStyleSet(getter_AddRefs(set));
-        nsCOMPtr<nsIRuleNode> rootNode;
-        set->GetRuleTree(getter_AddRefs(rootNode));
-        if (rootNode)
-          rootNode->ClearCachedDataInSubtree(rule);
-      }
+      nsCOMPtr<nsIStyleSet> set;
+      shell->GetStyleSet(getter_AddRefs(set));
+      set->ClearStyleData(aPresContext, rule, styleContext);
     }
 
     // If there is no frame then there is no point in re-styling it,
@@ -10164,10 +10148,9 @@ nsCSSFrameConstructor::StyleRuleChanged(nsIPresContext* aPresContext,
   }
 
   if (restyle) {
-    nsIStyleContext* sc;
-    frame->GetStyleContext(&sc);
-    sc->RemapStyle(aPresContext);
-    NS_RELEASE(sc);
+    nsCOMPtr<nsIStyleSet> set;
+    shell->GetStyleSet(getter_AddRefs(set));
+    set->ClearStyleData(aPresContext, aStyleRule, nsnull);
   }
 
   if (reframe) {
diff --git a/mozilla/layout/style/nsStyleContext.cpp b/mozilla/layout/style/nsStyleContext.cpp
index 50613a4117a..7e62deb7992 100644
--- a/mozilla/layout/style/nsStyleContext.cpp
+++ b/mozilla/layout/style/nsStyleContext.cpp
@@ -75,8 +75,6 @@ public:
   virtual PRBool    Equals(const nsIStyleContext* aOther) const;
   virtual PRBool    HasTextDecorations() { return mBits & NS_STYLE_HAS_TEXT_DECORATIONS; };
 
-  NS_IMETHOD RemapStyle(nsIPresContext* aPresContext, PRBool aRecurse = PR_TRUE);
-
   NS_IMETHOD GetBorderPaddingFor(nsStyleBorderPadding& aBorderPadding);
 
   NS_IMETHOD GetStyle(nsStyleStructID aSID, const nsStyleStruct** aStruct);
@@ -89,6 +87,8 @@ public:
   virtual const nsStyleStruct* GetStyleData(nsStyleStructID aSID);
   virtual nsStyleStruct* GetUniqueStyleData(nsIPresContext* aPresContext, const nsStyleStructID& aSID);
 
+  virtual nsresult ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule);
+
   virtual void ForceUnique(void);
   NS_IMETHOD  CalcStyleDifference(nsIStyleContext* aOther, PRInt32& aHint,PRBool aStopAtFirstDifference = PR_FALSE);
 
@@ -104,6 +104,8 @@ protected:
   void AppendChild(nsStyleContext* aChild);
   void RemoveChild(nsStyleContext* aChild);
 
+  void ApplyStyleFixups(nsIPresContext* aPresContext);
+
   nsStyleContext* mParent;
   nsStyleContext* mChild;
   nsStyleContext* mEmptyChild;
@@ -140,33 +142,7 @@ nsStyleContext::nsStyleContext(nsIStyleContext* aParent,
     mParent->AppendChild(this);
   }
 
-  // See if we have any text decorations.
-  // First see if our parent has text decorations.  If our parent does, then we inherit the bit.
-  if (mParent && mParent->HasTextDecorations())
-    mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
-  else {
-    // We might have defined a decoration.
-    const nsStyleTextReset* text = (const nsStyleTextReset*)GetStyleData(eStyleStruct_TextReset);
-    if (text->mTextDecoration != NS_STYLE_TEXT_DECORATION_NONE &&
-        text->mTextDecoration != NS_STYLE_TEXT_DECORATION_OVERRIDE_ALL)
-      mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
-  }
-
-  // Correct tables.
-  const nsStyleDisplay* disp = (const nsStyleDisplay*)GetStyleData(eStyleStruct_Display);
-  if (disp->mDisplay == NS_STYLE_DISPLAY_TABLE) {
-    // -moz-center and -moz-right are used for HTML's alignment
-    // This is covering the <div align="right"><table>...</table></div> case.
-    // In this case, we don't want to inherit the text alignment into the table.
-    const nsStyleText* text = (const nsStyleText*)GetStyleData(eStyleStruct_Text);
-    
-    if (text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
-        text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)
-    {
-      nsStyleText* uniqueText = (nsStyleText*)GetUniqueStyleData(aPresContext, eStyleStruct_Text);
-      uniqueText->mTextAlign = NS_STYLE_TEXT_ALIGN_DEFAULT;
-    }
-  }
+  ApplyStyleFixups(aPresContext);
 }
 
 nsStyleContext::~nsStyleContext()
@@ -545,30 +521,60 @@ nsStyleContext::SetStyle(nsStyleStructID aSID, const nsStyleStruct& aStruct)
   return result;
 }
 
-NS_IMETHODIMP
-nsStyleContext::RemapStyle(nsIPresContext* aPresContext, PRBool aRecurse)
+void
+nsStyleContext::ApplyStyleFixups(nsIPresContext* aPresContext)
 {
-#if 0 // Commenting out until we figure out why this crashes only on opt builds.
-  // First we need to clear out all of our style data.
-  if (mCachedStyleData.mResetData || mCachedStyleData.mInheritedData)
-    mCachedStyleData.Destroy(mBits, aPresContext);
+  // See if we have any text decorations.
+  // First see if our parent has text decorations.  If our parent does, then we inherit the bit.
+  if (mParent && mParent->HasTextDecorations())
+    mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
+  else {
+    // We might have defined a decoration.
+    const nsStyleTextReset* text = (const nsStyleTextReset*)GetStyleData(eStyleStruct_TextReset);
+    if (text->mTextDecoration != NS_STYLE_TEXT_DECORATION_NONE &&
+        text->mTextDecoration != NS_STYLE_TEXT_DECORATION_OVERRIDE_ALL)
+      mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
+  }
 
-  mBits &= ~NS_STYLE_INHERIT_MASK;  // Clear out all data that indicates we should look for
-                                    // style data in our parent.
+  // Correct tables.
+  const nsStyleDisplay* disp = (const nsStyleDisplay*)GetStyleData(eStyleStruct_Display);
+  if (disp->mDisplay == NS_STYLE_DISPLAY_TABLE) {
+    // -moz-center and -moz-right are used for HTML's alignment
+    // This is covering the <div align="right"><table>...</table></div> case.
+    // In this case, we don't want to inherit the text alignment into the table.
+    const nsStyleText* text = (const nsStyleText*)GetStyleData(eStyleStruct_Text);
+    
+    if (text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
+        text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)
+    {
+      nsStyleText* uniqueText = (nsStyleText*)GetUniqueStyleData(aPresContext, eStyleStruct_Text);
+      uniqueText->mTextAlign = NS_STYLE_TEXT_ALIGN_DEFAULT;
+    }
+  }
+}
 
-  // Now we need to ensure that any cached data along the path from our
-  // rule node back to the root is cleared out.
-  mRuleNode->ClearPath();
+nsresult
+nsStyleContext::ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule)
+{
+  PRBool matched = PR_TRUE;
+  if (aRule)
+    mRuleNode->PathContainsRule(aRule, &matched);
+  
+  if (matched) {
+    // First we need to clear out all of our style data.
+    if (mCachedStyleData.mResetData || mCachedStyleData.mInheritedData)
+      mCachedStyleData.Destroy(mBits, aPresContext);
 
-  // Now do the same for all of our children, but only if the recurse boolean
-  // is set.
-  if (!aRecurse)
-    return NS_OK;
+    mBits = 0; // Clear all bits.
+    aRule = nsnull;
+  }
+
+  ApplyStyleFixups(aPresContext);
 
   if (mChild) {
     nsStyleContext* child = mChild;
     do {
-      child->RemapStyle(aPresContext);
+      child->ClearStyleData(aPresContext, aRule);
       child = child->mNextSibling;
     } while (mChild != child);
   }
@@ -576,11 +582,11 @@ nsStyleContext::RemapStyle(nsIPresContext* aPresContext, PRBool aRecurse)
   if (mEmptyChild) {
     nsStyleContext* child = mEmptyChild;
     do {
-      child->RemapStyle(aPresContext);
+      child->ClearStyleData(aPresContext, aRule);
       child = child->mNextSibling;
     } while (mEmptyChild != child);
   }
-#endif
+
   return NS_OK;
 }
 
diff --git a/mozilla/layout/style/nsStyleSet.cpp b/mozilla/layout/style/nsStyleSet.cpp
index 2ed87c83f2a..44921c48b5e 100644
--- a/mozilla/layout/style/nsStyleSet.cpp
+++ b/mozilla/layout/style/nsStyleSet.cpp
@@ -115,6 +115,7 @@ public:
   NS_IMETHOD Shutdown();
 
   virtual nsresult GetRuleTree(nsIRuleNode** aResult);
+  virtual nsresult ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule, nsIStyleContext* aContext);
 
   NS_IMETHOD ReParentStyleContext(nsIPresContext* aPresContext,
                                   nsIStyleContext* aStyleContext, 
@@ -985,6 +986,53 @@ StyleSetImpl::GetRuleTree(nsIRuleNode** aResult)
   return NS_OK;
 }
 
+nsresult
+StyleSetImpl::ClearStyleData(nsIPresContext* aPresContext, nsIStyleRule* aRule, nsIStyleContext* aContext)
+{
+  // XXXdwh.  If we're willing to *really* optimize this
+  // invalidation, we could only invalidate the struct data
+  // that actually changed.  For example, if someone changes
+  // style.left, we really only need to blow away cached
+  // data in the position struct.
+  if (aContext) {
+    nsCOMPtr<nsIRuleNode> ruleNode;
+    aContext->GetRuleNode(getter_AddRefs(ruleNode));
+    ruleNode->ClearCachedData(aRule); 
+
+    // We don't need to mess with the style tree in this case, since the act of 
+    // changing inline style attributes automatically causes re-resolution to a new style context
+    // (with new descendant style contexts as well).
+  }
+  else {
+    // XXXdwh This is not terribly fast, but fortunately this case is rare (and often a full tree
+    // invalidation anyway).  Improving performance here would involve a footprint
+    // increase.  Mappings from rule nodes to their associated style contexts as well as
+    // mappings from rules to their associated rule nodes would enable us to avoid the two
+    // tree walks that occur here.
+
+    // Crawl the entire rule tree and blow away all data for rule nodes (and their descendants)
+    // that have the given rule.
+    if (mRuleTree)
+      mRuleTree->ClearCachedDataInSubtree(aRule);
+
+    // We need to crawl the entire style context tree, and for each style context we need 
+    // to see if the specified rule is matched.  If so, that context and all its descendant
+    // contexts must have their data wiped.
+    nsCOMPtr<nsIPresShell> shell;
+    aPresContext->GetShell(getter_AddRefs(shell));
+    nsIFrame* rootFrame;
+    shell->GetRootFrame(&rootFrame);
+    if (rootFrame) {
+      nsCOMPtr<nsIStyleContext> rootContext;
+      rootFrame->GetStyleContext(getter_AddRefs(rootContext));
+      if (rootContext)
+        rootContext->ClearStyleData(aPresContext, aRule);
+    }
+  }
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 StyleSetImpl::ReParentStyleContext(nsIPresContext* aPresContext,
                                    nsIStyleContext* aStyleContext,