diff --git a/content/base/src/nsStyleContext.cpp b/content/base/src/nsStyleContext.cpp
index a520fa357f49..2736bf1647be 100644
--- a/content/base/src/nsStyleContext.cpp
+++ b/content/base/src/nsStyleContext.cpp
@@ -566,6 +566,8 @@ public:
   virtual nsIStyleContext*  GetParent(void) const;
   virtual nsISupportsArray* GetStyleRules(void) const;
   virtual PRInt32 GetStyleRuleCount(void) const;
+  virtual PRInt32 GetBackstopStyleRuleCount(void) const;
+  virtual void SetBackstopStyleRuleCount(PRInt32 aCount);
 
   virtual nsIStyleContext* FindChildWithContent(nsIContent* aContent);
   virtual nsIStyleContext* FindChildWithRules(nsISupportsArray* aRules);
@@ -599,6 +601,7 @@ protected:
   PRUint32          mHashValid: 1;
   PRUint32          mHashValue: 31;
   nsISupportsArray* mRules;
+  PRInt32           mBackstopRuleCount;
   PRInt32           mDataCode;
 
   // the style data...
@@ -631,6 +634,7 @@ StyleContextImpl::StyleContextImpl(nsIStyleContext* aParent,
     mChild(nsnull),
     mContent(aContent),
     mRules(aRules),
+    mBackstopRuleCount(0),
     mDataCode(-1),
     mFont(aPresContext->GetDefaultFont(), aPresContext->GetDefaultFixedFont()),
     mColor(),
@@ -754,6 +758,17 @@ PRInt32 StyleContextImpl::GetStyleRuleCount(void) const
   return 0;
 }
 
+PRInt32 StyleContextImpl::GetBackstopStyleRuleCount(void) const
+{
+  return mBackstopRuleCount;
+}
+
+void StyleContextImpl::SetBackstopStyleRuleCount(PRInt32 aCount)
+{
+  NS_PRECONDITION(aCount <= GetStyleRuleCount(), "bad backstop rule count");
+  mBackstopRuleCount = aCount;
+}
+
 nsIStyleContext* StyleContextImpl::FindChildWithContent(nsIContent* aContent)
 {
   nsIStyleContext* result = nsnull;
@@ -930,7 +945,7 @@ nsStyleStruct* StyleContextImpl::GetMutableStyleData(nsStyleStructID aSID)
   }
   if (nsnull != result) {
     if (0 == mDataCode) {
-      mDataCode = ++gLastDataCode;
+//      mDataCode = ++gLastDataCode;  // XXX temp disable, this is still used but not needed to force unique
     }
   }
   return result;
@@ -978,7 +993,7 @@ void StyleContextImpl::RemapStyle(nsIPresContext* aPresContext)
 
   if ((nsnull != mRules) && (0 < mRules->Count())) {
     MapStyleData  data(this, aPresContext);
-    mRules->EnumerateBackwards(MapStyleRule, &data);
+    mRules->EnumerateForwards(MapStyleRule, &data);
   }
   if (-1 == mDataCode) {
     mDataCode = 0;
@@ -998,7 +1013,7 @@ void StyleContextImpl::RemapStyle(nsIPresContext* aPresContext)
 
     if ((nsnull != mRules) && (0 < mRules->Count())) {
       MapStyleData  data(this, aPresContext);
-      mRules->EnumerateBackwards(MapStyleRule, &data);
+      mRules->EnumerateForwards(MapStyleRule, &data);
     }
   }
 }
diff --git a/content/base/src/nsStyleSet.cpp b/content/base/src/nsStyleSet.cpp
index 8532340cbbfc..af43f937da22 100644
--- a/content/base/src/nsStyleSet.cpp
+++ b/content/base/src/nsStyleSet.cpp
@@ -453,9 +453,8 @@ PRInt32 StyleSetImpl::RulesMatching(nsISupportsArray* aSheets,
   PRInt32 ruleCount = 0;
 
   if (nsnull != aSheets) {
-    PRInt32 sheetCount = aSheets->Count();
-    PRInt32 index;
-    for (index = 0; index < sheetCount; index++) {
+    PRInt32 index = aSheets->Count();
+    while (0 < index--) {
       nsIStyleSheet* sheet = (nsIStyleSheet*)aSheets->ElementAt(index);
       ruleCount += sheet->RulesMatching(aPresContext, aContent, aParentFrame,
                                         aResults);
@@ -549,11 +548,15 @@ nsIStyleContext* StyleSetImpl::ResolveStyleFor(nsIPresContext* aPresContext,
 
     nsISupportsArray*  rules = nsnull;
     if (NS_OK == NS_NewISupportsArray(&rules)) {
-      PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aContent, aParentFrame, rules);
+      PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aContent, aParentFrame, rules);
+      PRInt32 backstopRules = ruleCount;
       ruleCount += RulesMatching(mDocSheets, aPresContext, aContent, aParentFrame, rules);
-      ruleCount += RulesMatching(mBackstopSheets, aPresContext, aContent, aParentFrame, rules);
+      ruleCount += RulesMatching(mOverrideSheets, aPresContext, aContent, aParentFrame, rules);
 
       result = GetContext(aPresContext, aParentFrame, aContent, parentContext, rules, aForceUnique);
+      if (nsnull != result) {
+        result->SetBackstopStyleRuleCount(backstopRules);
+      }
 
       NS_RELEASE(rules);
     }
@@ -574,9 +577,8 @@ PRInt32 StyleSetImpl::RulesMatching(nsISupportsArray* aSheets,
   PRInt32 ruleCount = 0;
 
   if (nsnull != aSheets) {
-    PRInt32 sheetCount = aSheets->Count();
-    PRInt32 index;
-    for (index = 0; index < sheetCount; index++) {
+    PRInt32 index = aSheets->Count();
+    while (0 < index--) {
       nsIStyleSheet* sheet = (nsIStyleSheet*)aSheets->ElementAt(index);
       ruleCount += sheet->RulesMatching(aPresContext, aPseudoTag, aParentFrame,
                                         aResults);
@@ -605,11 +607,15 @@ nsIStyleContext* StyleSetImpl::ResolvePseudoStyleFor(nsIPresContext* aPresContex
 
   nsISupportsArray*  rules = nsnull;
   if (NS_OK == NS_NewISupportsArray(&rules)) {
-    PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 backstopRules = ruleCount;
     ruleCount += RulesMatching(mDocSheets, aPresContext, aPseudoTag, aParentFrame, rules);
-    ruleCount += RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    ruleCount += RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
 
     result = GetContext(aPresContext, aParentFrame, nsnull, parentContext, rules, aForceUnique);
+    if (nsnull != result) {
+      result->SetBackstopStyleRuleCount(backstopRules);
+    }
 
     NS_RELEASE(rules);
   }
@@ -638,12 +644,16 @@ nsIStyleContext* StyleSetImpl::ProbePseudoStyleFor(nsIPresContext* aPresContext,
 
   nsISupportsArray*  rules = nsnull;
   if (NS_OK == NS_NewISupportsArray(&rules)) {
-    PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 backstopRules = ruleCount;
     ruleCount += RulesMatching(mDocSheets, aPresContext, aPseudoTag, aParentFrame, rules);
-    ruleCount += RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    ruleCount += RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
 
     if (0 < ruleCount) {
       result = GetContext(aPresContext, aParentFrame, nsnull, parentContext, rules, aForceUnique);
+      if (nsnull != result) {
+        result->SetBackstopStyleRuleCount(backstopRules);
+      }
     }
 
     NS_RELEASE(rules);
diff --git a/layout/base/src/nsStyleContext.cpp b/layout/base/src/nsStyleContext.cpp
index a520fa357f49..2736bf1647be 100644
--- a/layout/base/src/nsStyleContext.cpp
+++ b/layout/base/src/nsStyleContext.cpp
@@ -566,6 +566,8 @@ public:
   virtual nsIStyleContext*  GetParent(void) const;
   virtual nsISupportsArray* GetStyleRules(void) const;
   virtual PRInt32 GetStyleRuleCount(void) const;
+  virtual PRInt32 GetBackstopStyleRuleCount(void) const;
+  virtual void SetBackstopStyleRuleCount(PRInt32 aCount);
 
   virtual nsIStyleContext* FindChildWithContent(nsIContent* aContent);
   virtual nsIStyleContext* FindChildWithRules(nsISupportsArray* aRules);
@@ -599,6 +601,7 @@ protected:
   PRUint32          mHashValid: 1;
   PRUint32          mHashValue: 31;
   nsISupportsArray* mRules;
+  PRInt32           mBackstopRuleCount;
   PRInt32           mDataCode;
 
   // the style data...
@@ -631,6 +634,7 @@ StyleContextImpl::StyleContextImpl(nsIStyleContext* aParent,
     mChild(nsnull),
     mContent(aContent),
     mRules(aRules),
+    mBackstopRuleCount(0),
     mDataCode(-1),
     mFont(aPresContext->GetDefaultFont(), aPresContext->GetDefaultFixedFont()),
     mColor(),
@@ -754,6 +758,17 @@ PRInt32 StyleContextImpl::GetStyleRuleCount(void) const
   return 0;
 }
 
+PRInt32 StyleContextImpl::GetBackstopStyleRuleCount(void) const
+{
+  return mBackstopRuleCount;
+}
+
+void StyleContextImpl::SetBackstopStyleRuleCount(PRInt32 aCount)
+{
+  NS_PRECONDITION(aCount <= GetStyleRuleCount(), "bad backstop rule count");
+  mBackstopRuleCount = aCount;
+}
+
 nsIStyleContext* StyleContextImpl::FindChildWithContent(nsIContent* aContent)
 {
   nsIStyleContext* result = nsnull;
@@ -930,7 +945,7 @@ nsStyleStruct* StyleContextImpl::GetMutableStyleData(nsStyleStructID aSID)
   }
   if (nsnull != result) {
     if (0 == mDataCode) {
-      mDataCode = ++gLastDataCode;
+//      mDataCode = ++gLastDataCode;  // XXX temp disable, this is still used but not needed to force unique
     }
   }
   return result;
@@ -978,7 +993,7 @@ void StyleContextImpl::RemapStyle(nsIPresContext* aPresContext)
 
   if ((nsnull != mRules) && (0 < mRules->Count())) {
     MapStyleData  data(this, aPresContext);
-    mRules->EnumerateBackwards(MapStyleRule, &data);
+    mRules->EnumerateForwards(MapStyleRule, &data);
   }
   if (-1 == mDataCode) {
     mDataCode = 0;
@@ -998,7 +1013,7 @@ void StyleContextImpl::RemapStyle(nsIPresContext* aPresContext)
 
     if ((nsnull != mRules) && (0 < mRules->Count())) {
       MapStyleData  data(this, aPresContext);
-      mRules->EnumerateBackwards(MapStyleRule, &data);
+      mRules->EnumerateForwards(MapStyleRule, &data);
     }
   }
 }
diff --git a/layout/base/src/nsStyleSet.cpp b/layout/base/src/nsStyleSet.cpp
index 8532340cbbfc..af43f937da22 100644
--- a/layout/base/src/nsStyleSet.cpp
+++ b/layout/base/src/nsStyleSet.cpp
@@ -453,9 +453,8 @@ PRInt32 StyleSetImpl::RulesMatching(nsISupportsArray* aSheets,
   PRInt32 ruleCount = 0;
 
   if (nsnull != aSheets) {
-    PRInt32 sheetCount = aSheets->Count();
-    PRInt32 index;
-    for (index = 0; index < sheetCount; index++) {
+    PRInt32 index = aSheets->Count();
+    while (0 < index--) {
       nsIStyleSheet* sheet = (nsIStyleSheet*)aSheets->ElementAt(index);
       ruleCount += sheet->RulesMatching(aPresContext, aContent, aParentFrame,
                                         aResults);
@@ -549,11 +548,15 @@ nsIStyleContext* StyleSetImpl::ResolveStyleFor(nsIPresContext* aPresContext,
 
     nsISupportsArray*  rules = nsnull;
     if (NS_OK == NS_NewISupportsArray(&rules)) {
-      PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aContent, aParentFrame, rules);
+      PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aContent, aParentFrame, rules);
+      PRInt32 backstopRules = ruleCount;
       ruleCount += RulesMatching(mDocSheets, aPresContext, aContent, aParentFrame, rules);
-      ruleCount += RulesMatching(mBackstopSheets, aPresContext, aContent, aParentFrame, rules);
+      ruleCount += RulesMatching(mOverrideSheets, aPresContext, aContent, aParentFrame, rules);
 
       result = GetContext(aPresContext, aParentFrame, aContent, parentContext, rules, aForceUnique);
+      if (nsnull != result) {
+        result->SetBackstopStyleRuleCount(backstopRules);
+      }
 
       NS_RELEASE(rules);
     }
@@ -574,9 +577,8 @@ PRInt32 StyleSetImpl::RulesMatching(nsISupportsArray* aSheets,
   PRInt32 ruleCount = 0;
 
   if (nsnull != aSheets) {
-    PRInt32 sheetCount = aSheets->Count();
-    PRInt32 index;
-    for (index = 0; index < sheetCount; index++) {
+    PRInt32 index = aSheets->Count();
+    while (0 < index--) {
       nsIStyleSheet* sheet = (nsIStyleSheet*)aSheets->ElementAt(index);
       ruleCount += sheet->RulesMatching(aPresContext, aPseudoTag, aParentFrame,
                                         aResults);
@@ -605,11 +607,15 @@ nsIStyleContext* StyleSetImpl::ResolvePseudoStyleFor(nsIPresContext* aPresContex
 
   nsISupportsArray*  rules = nsnull;
   if (NS_OK == NS_NewISupportsArray(&rules)) {
-    PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 backstopRules = ruleCount;
     ruleCount += RulesMatching(mDocSheets, aPresContext, aPseudoTag, aParentFrame, rules);
-    ruleCount += RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    ruleCount += RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
 
     result = GetContext(aPresContext, aParentFrame, nsnull, parentContext, rules, aForceUnique);
+    if (nsnull != result) {
+      result->SetBackstopStyleRuleCount(backstopRules);
+    }
 
     NS_RELEASE(rules);
   }
@@ -638,12 +644,16 @@ nsIStyleContext* StyleSetImpl::ProbePseudoStyleFor(nsIPresContext* aPresContext,
 
   nsISupportsArray*  rules = nsnull;
   if (NS_OK == NS_NewISupportsArray(&rules)) {
-    PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 backstopRules = ruleCount;
     ruleCount += RulesMatching(mDocSheets, aPresContext, aPseudoTag, aParentFrame, rules);
-    ruleCount += RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    ruleCount += RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
 
     if (0 < ruleCount) {
       result = GetContext(aPresContext, aParentFrame, nsnull, parentContext, rules, aForceUnique);
+      if (nsnull != result) {
+        result->SetBackstopStyleRuleCount(backstopRules);
+      }
     }
 
     NS_RELEASE(rules);
diff --git a/layout/style/nsStyleContext.cpp b/layout/style/nsStyleContext.cpp
index a520fa357f49..2736bf1647be 100644
--- a/layout/style/nsStyleContext.cpp
+++ b/layout/style/nsStyleContext.cpp
@@ -566,6 +566,8 @@ public:
   virtual nsIStyleContext*  GetParent(void) const;
   virtual nsISupportsArray* GetStyleRules(void) const;
   virtual PRInt32 GetStyleRuleCount(void) const;
+  virtual PRInt32 GetBackstopStyleRuleCount(void) const;
+  virtual void SetBackstopStyleRuleCount(PRInt32 aCount);
 
   virtual nsIStyleContext* FindChildWithContent(nsIContent* aContent);
   virtual nsIStyleContext* FindChildWithRules(nsISupportsArray* aRules);
@@ -599,6 +601,7 @@ protected:
   PRUint32          mHashValid: 1;
   PRUint32          mHashValue: 31;
   nsISupportsArray* mRules;
+  PRInt32           mBackstopRuleCount;
   PRInt32           mDataCode;
 
   // the style data...
@@ -631,6 +634,7 @@ StyleContextImpl::StyleContextImpl(nsIStyleContext* aParent,
     mChild(nsnull),
     mContent(aContent),
     mRules(aRules),
+    mBackstopRuleCount(0),
     mDataCode(-1),
     mFont(aPresContext->GetDefaultFont(), aPresContext->GetDefaultFixedFont()),
     mColor(),
@@ -754,6 +758,17 @@ PRInt32 StyleContextImpl::GetStyleRuleCount(void) const
   return 0;
 }
 
+PRInt32 StyleContextImpl::GetBackstopStyleRuleCount(void) const
+{
+  return mBackstopRuleCount;
+}
+
+void StyleContextImpl::SetBackstopStyleRuleCount(PRInt32 aCount)
+{
+  NS_PRECONDITION(aCount <= GetStyleRuleCount(), "bad backstop rule count");
+  mBackstopRuleCount = aCount;
+}
+
 nsIStyleContext* StyleContextImpl::FindChildWithContent(nsIContent* aContent)
 {
   nsIStyleContext* result = nsnull;
@@ -930,7 +945,7 @@ nsStyleStruct* StyleContextImpl::GetMutableStyleData(nsStyleStructID aSID)
   }
   if (nsnull != result) {
     if (0 == mDataCode) {
-      mDataCode = ++gLastDataCode;
+//      mDataCode = ++gLastDataCode;  // XXX temp disable, this is still used but not needed to force unique
     }
   }
   return result;
@@ -978,7 +993,7 @@ void StyleContextImpl::RemapStyle(nsIPresContext* aPresContext)
 
   if ((nsnull != mRules) && (0 < mRules->Count())) {
     MapStyleData  data(this, aPresContext);
-    mRules->EnumerateBackwards(MapStyleRule, &data);
+    mRules->EnumerateForwards(MapStyleRule, &data);
   }
   if (-1 == mDataCode) {
     mDataCode = 0;
@@ -998,7 +1013,7 @@ void StyleContextImpl::RemapStyle(nsIPresContext* aPresContext)
 
     if ((nsnull != mRules) && (0 < mRules->Count())) {
       MapStyleData  data(this, aPresContext);
-      mRules->EnumerateBackwards(MapStyleRule, &data);
+      mRules->EnumerateForwards(MapStyleRule, &data);
     }
   }
 }
diff --git a/layout/style/nsStyleSet.cpp b/layout/style/nsStyleSet.cpp
index 8532340cbbfc..af43f937da22 100644
--- a/layout/style/nsStyleSet.cpp
+++ b/layout/style/nsStyleSet.cpp
@@ -453,9 +453,8 @@ PRInt32 StyleSetImpl::RulesMatching(nsISupportsArray* aSheets,
   PRInt32 ruleCount = 0;
 
   if (nsnull != aSheets) {
-    PRInt32 sheetCount = aSheets->Count();
-    PRInt32 index;
-    for (index = 0; index < sheetCount; index++) {
+    PRInt32 index = aSheets->Count();
+    while (0 < index--) {
       nsIStyleSheet* sheet = (nsIStyleSheet*)aSheets->ElementAt(index);
       ruleCount += sheet->RulesMatching(aPresContext, aContent, aParentFrame,
                                         aResults);
@@ -549,11 +548,15 @@ nsIStyleContext* StyleSetImpl::ResolveStyleFor(nsIPresContext* aPresContext,
 
     nsISupportsArray*  rules = nsnull;
     if (NS_OK == NS_NewISupportsArray(&rules)) {
-      PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aContent, aParentFrame, rules);
+      PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aContent, aParentFrame, rules);
+      PRInt32 backstopRules = ruleCount;
       ruleCount += RulesMatching(mDocSheets, aPresContext, aContent, aParentFrame, rules);
-      ruleCount += RulesMatching(mBackstopSheets, aPresContext, aContent, aParentFrame, rules);
+      ruleCount += RulesMatching(mOverrideSheets, aPresContext, aContent, aParentFrame, rules);
 
       result = GetContext(aPresContext, aParentFrame, aContent, parentContext, rules, aForceUnique);
+      if (nsnull != result) {
+        result->SetBackstopStyleRuleCount(backstopRules);
+      }
 
       NS_RELEASE(rules);
     }
@@ -574,9 +577,8 @@ PRInt32 StyleSetImpl::RulesMatching(nsISupportsArray* aSheets,
   PRInt32 ruleCount = 0;
 
   if (nsnull != aSheets) {
-    PRInt32 sheetCount = aSheets->Count();
-    PRInt32 index;
-    for (index = 0; index < sheetCount; index++) {
+    PRInt32 index = aSheets->Count();
+    while (0 < index--) {
       nsIStyleSheet* sheet = (nsIStyleSheet*)aSheets->ElementAt(index);
       ruleCount += sheet->RulesMatching(aPresContext, aPseudoTag, aParentFrame,
                                         aResults);
@@ -605,11 +607,15 @@ nsIStyleContext* StyleSetImpl::ResolvePseudoStyleFor(nsIPresContext* aPresContex
 
   nsISupportsArray*  rules = nsnull;
   if (NS_OK == NS_NewISupportsArray(&rules)) {
-    PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 backstopRules = ruleCount;
     ruleCount += RulesMatching(mDocSheets, aPresContext, aPseudoTag, aParentFrame, rules);
-    ruleCount += RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    ruleCount += RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
 
     result = GetContext(aPresContext, aParentFrame, nsnull, parentContext, rules, aForceUnique);
+    if (nsnull != result) {
+      result->SetBackstopStyleRuleCount(backstopRules);
+    }
 
     NS_RELEASE(rules);
   }
@@ -638,12 +644,16 @@ nsIStyleContext* StyleSetImpl::ProbePseudoStyleFor(nsIPresContext* aPresContext,
 
   nsISupportsArray*  rules = nsnull;
   if (NS_OK == NS_NewISupportsArray(&rules)) {
-    PRInt32 ruleCount = RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 ruleCount = RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    PRInt32 backstopRules = ruleCount;
     ruleCount += RulesMatching(mDocSheets, aPresContext, aPseudoTag, aParentFrame, rules);
-    ruleCount += RulesMatching(mBackstopSheets, aPresContext, aPseudoTag, aParentFrame, rules);
+    ruleCount += RulesMatching(mOverrideSheets, aPresContext, aPseudoTag, aParentFrame, rules);
 
     if (0 < ruleCount) {
       result = GetContext(aPresContext, aParentFrame, nsnull, parentContext, rules, aForceUnique);
+      if (nsnull != result) {
+        result->SetBackstopStyleRuleCount(backstopRules);
+      }
     }
 
     NS_RELEASE(rules);