diff --git a/content/base/src/nsDocumentViewer.cpp b/content/base/src/nsDocumentViewer.cpp
index b2ac92a7760..9781ff56128 100644
--- a/content/base/src/nsDocumentViewer.cpp
+++ b/content/base/src/nsDocumentViewer.cpp
@@ -1824,6 +1824,7 @@ DocumentViewerImpl::SetDOMDocument(nsIDOMDocument *aDocument)
 NS_IMETHODIMP
 DocumentViewerImpl::SetUAStyleSheet(nsIStyleSheet* aUAStyleSheet)
 {
+  NS_ASSERTION(aUAStyleSheet, "unexpected null pointer");
   if (aUAStyleSheet) {
     nsCOMPtr<nsICSSStyleSheet> sheet(do_QueryInterface(aUAStyleSheet));
     nsCOMPtr<nsICSSStyleSheet> newSheet;
@@ -3838,14 +3839,15 @@ DocumentViewerImpl::ReflowPrintObject(PrintObject * aPO, PRBool aDoCalcShrink)
   }
 #endif // NS_PRINT_PREVIEW
 
+  nsCompatibility mode;
+  mPresContext->GetCompatibilityMode(&mode);
+
   // Setup hierarchical relationship in view manager
   aPO->mViewManager->SetRootView(aPO->mRootView);
   aPO->mPresShell->Init(document, aPO->mPresContext,
-                        aPO->mViewManager, aPO->mStyleSet);
+                        aPO->mViewManager, aPO->mStyleSet,
+                        mode != eCompatibility_Standard);
 
-  nsCompatibility mode;
-  mPresContext->GetCompatibilityMode(&mode);
-  aPO->mPresContext->SetCompatibilityMode(mode);
   if (!containerIsSet) {
     nsCOMPtr<nsISupports> supps(do_QueryInterface(aPO->mWebShell));
     aPO->mPresContext->SetContainer(supps);
diff --git a/content/base/src/nsStyleSet.cpp b/content/base/src/nsStyleSet.cpp
index dfdf41c317f..dfb535bf0a3 100644
--- a/content/base/src/nsStyleSet.cpp
+++ b/content/base/src/nsStyleSet.cpp
@@ -864,9 +864,23 @@ NS_IMETHODIMP StyleSetImpl::EnableQuirkStyleSheet(PRBool aEnable)
       }
     }
   }
+  NS_ASSERTION(mQuirkStyleSheet, "no quirk stylesheet");
   if (mQuirkStyleSheet) {
 #if defined(DEBUG_warren) || defined(DEBUG_attinasi)
     printf( "%s Quirk StyleSheet\n", aEnable ? "Enabling" : "Disabling" );
+#endif
+#ifdef DEBUG
+    PRUint32 count = 0;
+    if (mAgentRuleProcessors)
+      mAgentRuleProcessors->Count(&count);
+    PRBool enabledNow;
+    mQuirkStyleSheet->GetEnabled(enabledNow);
+    NS_ASSERTION(count == 0 || aEnable == enabledNow,
+                 "enabling/disabling quirk stylesheet too late");
+#ifdef DEBUG_dbaron
+    if (count != 0 && aEnable == enabledNow)
+      printf("WARNING: We set the quirks mode too many times.\n"); // we do!
+#endif
 #endif
     mQuirkStyleSheet->SetEnabled(aEnable);
   }
diff --git a/content/html/document/src/nsHTMLDocument.cpp b/content/html/document/src/nsHTMLDocument.cpp
index 1b90ef84821..006510c72da 100644
--- a/content/html/document/src/nsHTMLDocument.cpp
+++ b/content/html/document/src/nsHTMLDocument.cpp
@@ -495,17 +495,8 @@ nsHTMLDocument::CreateShell(nsIPresContext* aContext,
                             nsIStyleSet* aStyleSet,
                             nsIPresShell** aInstancePtrResult)
 {
-  nsresult result = nsMarkupDocument::CreateShell(aContext,
-                                                  aViewManager,
-                                                  aStyleSet,
-                                                  aInstancePtrResult);
-
-  if (NS_SUCCEEDED(result)) {
-    aContext->SetCompatibilityMode(((eDTDMode_strict== mDTDMode) ? 
-                                    eCompatibility_Standard : 
-                                    eCompatibility_NavQuirks));
-  }
-  return result;
+  return doCreateShell(aContext, aViewManager, aStyleSet,
+                       eDTDMode_strict != mDTDMode, aInstancePtrResult);
 }
 
 // The following Try*Charset will return PR_FALSE only if the charset source 
diff --git a/content/html/document/src/nsMarkupDocument.cpp b/content/html/document/src/nsMarkupDocument.cpp
index b942f4fa3f8..0ee05f0c5d0 100644
--- a/content/html/document/src/nsMarkupDocument.cpp
+++ b/content/html/document/src/nsMarkupDocument.cpp
@@ -61,11 +61,22 @@ nsMarkupDocument::CreateShell(nsIPresContext* aContext,
                               nsIViewManager* aViewManager,
                               nsIStyleSet* aStyleSet,
                               nsIPresShell** aInstancePtrResult)
+{
+  // Don't add anything here.  Add it to |doCreateShell| instead.  This
+  // exists so nsHTMLDocument can pass PR_TRUE for the 4th parameter
+  // some of the time.
+  return doCreateShell(aContext, aViewManager, aStyleSet, PR_FALSE,
+                       aInstancePtrResult);
+}
+
+nsresult
+nsMarkupDocument::doCreateShell(nsIPresContext* aContext,
+                                nsIViewManager* aViewManager,
+                                nsIStyleSet* aStyleSet,
+                                PRBool aIsQuirksMode,
+                                nsIPresShell** aInstancePtrResult)
 {
   NS_PRECONDITION(nsnull != aInstancePtrResult, "null ptr");
-  if (nsnull == aInstancePtrResult) {
-    return NS_ERROR_NULL_POINTER;
-  }
 
   nsresult rv;
   nsCOMPtr<nsIPresShell> shell(do_CreateInstance(kPresShellCID,&rv));
@@ -73,7 +84,7 @@ nsMarkupDocument::CreateShell(nsIPresContext* aContext,
     return rv;
   }
 
-  rv = shell->Init(this, aContext, aViewManager, aStyleSet);
+  rv = shell->Init(this, aContext, aViewManager, aStyleSet, aIsQuirksMode);
   if (NS_FAILED(rv)) {
     return rv;
   }
@@ -83,11 +94,6 @@ nsMarkupDocument::CreateShell(nsIPresContext* aContext,
   *aInstancePtrResult = shell.get();
   NS_ADDREF(*aInstancePtrResult);
 
-  // tell the context the mode we want (always standard, which
-  // should be correct for everything except HTML)
-  // nsHTMLDocument overrides this method and sets it differently
-  aContext->SetCompatibilityMode(eCompatibility_Standard);
-
   return NS_OK;
 }
 
diff --git a/content/html/document/src/nsMarkupDocument.h b/content/html/document/src/nsMarkupDocument.h
index 52fddec8a5a..83730ed99d7 100644
--- a/content/html/document/src/nsMarkupDocument.h
+++ b/content/html/document/src/nsMarkupDocument.h
@@ -62,6 +62,15 @@ public:
                          nsIViewManager* aViewManager,
                          nsIStyleSet* aStyleSet,
                          nsIPresShell** aInstancePtrResult);
+protected:
+  // To allow different implementations to choose the quirks mode
+  // differently for their |CreateShell| without overriding the whole
+  // thing.
+  nsresult doCreateShell(nsIPresContext* aContext,
+                         nsIViewManager* aViewManager,
+                         nsIStyleSet* aStyleSet,
+                         PRBool aIsQuirksMode,
+                         nsIPresShell** aInstancePtrResult);
 };
 
 #endif /* nsMarkupDocument_h___ */
diff --git a/content/xul/document/src/nsXULDocument.cpp b/content/xul/document/src/nsXULDocument.cpp
index b8b51d720db..be53541ad29 100644
--- a/content/xul/document/src/nsXULDocument.cpp
+++ b/content/xul/document/src/nsXULDocument.cpp
@@ -1053,19 +1053,14 @@ nsXULDocument::CreateShell(nsIPresContext* aContext,
                            nsIPresShell** aInstancePtrResult)
 {
     NS_PRECONDITION(aInstancePtrResult, "null ptr");
-    if (! aInstancePtrResult)
-        return NS_ERROR_NULL_POINTER;
-
-    nsresult rv;
 
     nsIPresShell* shell;
-    if (NS_FAILED(rv = nsComponentManager::CreateInstance(kPresShellCID,
-                                                    nsnull,
-                                                    NS_GET_IID(nsIPresShell),
-                                                    (void**) &shell)))
+    nsresult rv = CallCreateInstance(kPresShellCID, &shell);
+    if (NS_FAILED(rv))
         return rv;
 
-    if (NS_FAILED(rv = shell->Init(this, aContext, aViewManager, aStyleSet))) {
+    rv = shell->Init(this, aContext, aViewManager, aStyleSet, PR_FALSE);
+    if (NS_FAILED(rv)) {
         NS_RELEASE(shell);
         return rv;
     }
@@ -1073,9 +1068,6 @@ nsXULDocument::CreateShell(nsIPresContext* aContext,
     mPresShells.AppendElement(shell);
     *aInstancePtrResult = shell; // addref implicit in CreateInstance()
 
-    // tell the context the mode we want (always standard)
-    aContext->SetCompatibilityMode(eCompatibility_Standard);
-
     return NS_OK;
 }
 
diff --git a/layout/base/nsDocumentViewer.cpp b/layout/base/nsDocumentViewer.cpp
index b2ac92a7760..9781ff56128 100644
--- a/layout/base/nsDocumentViewer.cpp
+++ b/layout/base/nsDocumentViewer.cpp
@@ -1824,6 +1824,7 @@ DocumentViewerImpl::SetDOMDocument(nsIDOMDocument *aDocument)
 NS_IMETHODIMP
 DocumentViewerImpl::SetUAStyleSheet(nsIStyleSheet* aUAStyleSheet)
 {
+  NS_ASSERTION(aUAStyleSheet, "unexpected null pointer");
   if (aUAStyleSheet) {
     nsCOMPtr<nsICSSStyleSheet> sheet(do_QueryInterface(aUAStyleSheet));
     nsCOMPtr<nsICSSStyleSheet> newSheet;
@@ -3838,14 +3839,15 @@ DocumentViewerImpl::ReflowPrintObject(PrintObject * aPO, PRBool aDoCalcShrink)
   }
 #endif // NS_PRINT_PREVIEW
 
+  nsCompatibility mode;
+  mPresContext->GetCompatibilityMode(&mode);
+
   // Setup hierarchical relationship in view manager
   aPO->mViewManager->SetRootView(aPO->mRootView);
   aPO->mPresShell->Init(document, aPO->mPresContext,
-                        aPO->mViewManager, aPO->mStyleSet);
+                        aPO->mViewManager, aPO->mStyleSet,
+                        mode != eCompatibility_Standard);
 
-  nsCompatibility mode;
-  mPresContext->GetCompatibilityMode(&mode);
-  aPO->mPresContext->SetCompatibilityMode(mode);
   if (!containerIsSet) {
     nsCOMPtr<nsISupports> supps(do_QueryInterface(aPO->mWebShell));
     aPO->mPresContext->SetContainer(supps);
diff --git a/layout/base/nsIPresShell.h b/layout/base/nsIPresShell.h
index 4b41a604367..cc577ff8fa6 100644
--- a/layout/base/nsIPresShell.h
+++ b/layout/base/nsIPresShell.h
@@ -125,7 +125,8 @@ public:
   NS_IMETHOD Init(nsIDocument* aDocument,
                   nsIPresContext* aPresContext,
                   nsIViewManager* aViewManager,
-                  nsIStyleSet* aStyleSet) = 0;
+                  nsIStyleSet* aStyleSet,
+                  PRBool aIsQuirksMode) = 0;
 
   /**
    * All callers are responsible for calling |Destroy| after calling
diff --git a/layout/base/nsPresContext.cpp b/layout/base/nsPresContext.cpp
index 608891d97b2..17649cf388a 100644
--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -150,7 +150,6 @@ nsPresContext::nsPresContext()
 {
   NS_INIT_REFCNT();
   mCompatibilityMode = eCompatibility_Standard;
-  mCompatibilityLocked = PR_FALSE;
   mWidgetRenderingMode = eWidgetRendering_Gfx; 
   mImageAnimationMode = imgIContainer::kNormalAnimMode;
   mImageAnimationModePref = imgIContainer::kNormalAnimMode;
@@ -454,27 +453,6 @@ nsPresContext::GetUserPreferences()
     mFontScaler = prefInt;
   }
 
-  if (NS_SUCCEEDED(mPrefs->GetIntPref("nglayout.compatibility.mode", &prefInt))) {
-    // XXX this should really be a state on the webshell instead of using prefs
-    switch (prefInt) {
-      case 1: 
-        mCompatibilityLocked = PR_TRUE;  
-        mCompatibilityMode = eCompatibility_Standard;   
-        break;
-      case 2: 
-        mCompatibilityLocked = PR_TRUE;  
-        mCompatibilityMode = eCompatibility_NavQuirks;  
-        break;
-      case 0:   // auto
-      default:
-        mCompatibilityLocked = PR_FALSE;  
-        break;
-    }
-  }
-  else {
-    mCompatibilityLocked = PR_FALSE;  // auto
-  }
-
   if (NS_SUCCEEDED(mPrefs->GetIntPref("nglayout.widget.mode", &prefInt))) {
     mWidgetRenderingMode = (enum nsWidgetRendering)prefInt;  // bad cast
   }
@@ -783,18 +761,15 @@ nsPresContext::GetCompatibilityMode(nsCompatibility* aResult)
 NS_IMETHODIMP
 nsPresContext::SetCompatibilityMode(nsCompatibility aMode)
 {
-  if (! mCompatibilityLocked) {
-    mCompatibilityMode = aMode;
-  }
+  mCompatibilityMode = aMode;
+
+  NS_ENSURE_TRUE(mShell, NS_OK);
 
   // enable/disable the QuirkSheet
-  NS_ASSERTION(mShell, "PresShell must be set on PresContext before calling nsPresContext::SetCompatibilityMode");
-  if (mShell) {
-    nsCOMPtr<nsIStyleSet> set;
-    nsresult rv = mShell->GetStyleSet(getter_AddRefs(set));
-    if (NS_SUCCEEDED(rv) && set) {
-      set->EnableQuirkStyleSheet((mCompatibilityMode != eCompatibility_Standard) ? PR_TRUE : PR_FALSE);
-    }
+  nsCOMPtr<nsIStyleSet> set;
+  mShell->GetStyleSet(getter_AddRefs(set));
+  if (set) {
+    set->EnableQuirkStyleSheet(mCompatibilityMode != eCompatibility_Standard);
   }
   return NS_OK;
 }
@@ -1477,6 +1452,8 @@ nsPresContext::LoadImage(const nsString& aURL,
       rv = content->GetDocument(*getter_AddRefs(document));
 
       // If there is no document, skip the policy check
+      // XXXldb This really means the document is being destroyed, so
+      // perhaps we're better off skipping the load entirely.
       if (document) {
         nsCOMPtr<nsIScriptGlobalObject> globalScript;
         rv = document->GetScriptGlobalObject(getter_AddRefs(globalScript));
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 1f41cee5618..a5c4a9bff7d 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -1057,7 +1057,8 @@ public:
   NS_IMETHOD Init(nsIDocument* aDocument,
                   nsIPresContext* aPresContext,
                   nsIViewManager* aViewManager,
-                  nsIStyleSet* aStyleSet);
+                  nsIStyleSet* aStyleSet,
+                  PRBool aIsQuirksMode);
   NS_IMETHOD Destroy();
 
   NS_IMETHOD AllocateFrame(size_t aSize, void** aResult);
@@ -1678,7 +1679,8 @@ NS_IMETHODIMP
 PresShell::Init(nsIDocument* aDocument,
                 nsIPresContext* aPresContext,
                 nsIViewManager* aViewManager,
-                nsIStyleSet* aStyleSet)
+                nsIStyleSet* aStyleSet,
+                PRBool aIsQuirksMode)
 {
   NS_PRECONDITION(nsnull != aDocument, "null ptr");
   NS_PRECONDITION(nsnull != aPresContext, "null ptr");
@@ -1699,11 +1701,16 @@ PresShell::Init(nsIDocument* aDocument,
   mViewManager->SetViewObserver(this);
 
   // Bind the context to the presentation shell.
-  mPresContext = dont_QueryInterface(aPresContext);
+  mPresContext = aPresContext;
   aPresContext->SetShell(this);
 
   mStyleSet = aStyleSet;
 
+  // Set the compatibility mode after attaching the pres context and
+  // style set, but before creating any frames.
+  mPresContext->SetCompatibilityMode(aIsQuirksMode
+                         ? eCompatibility_NavQuirks : eCompatibility_Standard);
+
   mHistoryState = nsnull;
 
   nsresult result = nsComponentManager::CreateInstance(kFrameSelectionCID, nsnull,
diff --git a/layout/base/public/nsIPresShell.h b/layout/base/public/nsIPresShell.h
index 4b41a604367..cc577ff8fa6 100644
--- a/layout/base/public/nsIPresShell.h
+++ b/layout/base/public/nsIPresShell.h
@@ -125,7 +125,8 @@ public:
   NS_IMETHOD Init(nsIDocument* aDocument,
                   nsIPresContext* aPresContext,
                   nsIViewManager* aViewManager,
-                  nsIStyleSet* aStyleSet) = 0;
+                  nsIStyleSet* aStyleSet,
+                  PRBool aIsQuirksMode) = 0;
 
   /**
    * All callers are responsible for calling |Destroy| after calling
diff --git a/layout/base/src/nsPresContext.cpp b/layout/base/src/nsPresContext.cpp
index 608891d97b2..17649cf388a 100644
--- a/layout/base/src/nsPresContext.cpp
+++ b/layout/base/src/nsPresContext.cpp
@@ -150,7 +150,6 @@ nsPresContext::nsPresContext()
 {
   NS_INIT_REFCNT();
   mCompatibilityMode = eCompatibility_Standard;
-  mCompatibilityLocked = PR_FALSE;
   mWidgetRenderingMode = eWidgetRendering_Gfx; 
   mImageAnimationMode = imgIContainer::kNormalAnimMode;
   mImageAnimationModePref = imgIContainer::kNormalAnimMode;
@@ -454,27 +453,6 @@ nsPresContext::GetUserPreferences()
     mFontScaler = prefInt;
   }
 
-  if (NS_SUCCEEDED(mPrefs->GetIntPref("nglayout.compatibility.mode", &prefInt))) {
-    // XXX this should really be a state on the webshell instead of using prefs
-    switch (prefInt) {
-      case 1: 
-        mCompatibilityLocked = PR_TRUE;  
-        mCompatibilityMode = eCompatibility_Standard;   
-        break;
-      case 2: 
-        mCompatibilityLocked = PR_TRUE;  
-        mCompatibilityMode = eCompatibility_NavQuirks;  
-        break;
-      case 0:   // auto
-      default:
-        mCompatibilityLocked = PR_FALSE;  
-        break;
-    }
-  }
-  else {
-    mCompatibilityLocked = PR_FALSE;  // auto
-  }
-
   if (NS_SUCCEEDED(mPrefs->GetIntPref("nglayout.widget.mode", &prefInt))) {
     mWidgetRenderingMode = (enum nsWidgetRendering)prefInt;  // bad cast
   }
@@ -783,18 +761,15 @@ nsPresContext::GetCompatibilityMode(nsCompatibility* aResult)
 NS_IMETHODIMP
 nsPresContext::SetCompatibilityMode(nsCompatibility aMode)
 {
-  if (! mCompatibilityLocked) {
-    mCompatibilityMode = aMode;
-  }
+  mCompatibilityMode = aMode;
+
+  NS_ENSURE_TRUE(mShell, NS_OK);
 
   // enable/disable the QuirkSheet
-  NS_ASSERTION(mShell, "PresShell must be set on PresContext before calling nsPresContext::SetCompatibilityMode");
-  if (mShell) {
-    nsCOMPtr<nsIStyleSet> set;
-    nsresult rv = mShell->GetStyleSet(getter_AddRefs(set));
-    if (NS_SUCCEEDED(rv) && set) {
-      set->EnableQuirkStyleSheet((mCompatibilityMode != eCompatibility_Standard) ? PR_TRUE : PR_FALSE);
-    }
+  nsCOMPtr<nsIStyleSet> set;
+  mShell->GetStyleSet(getter_AddRefs(set));
+  if (set) {
+    set->EnableQuirkStyleSheet(mCompatibilityMode != eCompatibility_Standard);
   }
   return NS_OK;
 }
@@ -1477,6 +1452,8 @@ nsPresContext::LoadImage(const nsString& aURL,
       rv = content->GetDocument(*getter_AddRefs(document));
 
       // If there is no document, skip the policy check
+      // XXXldb This really means the document is being destroyed, so
+      // perhaps we're better off skipping the load entirely.
       if (document) {
         nsCOMPtr<nsIScriptGlobalObject> globalScript;
         rv = document->GetScriptGlobalObject(getter_AddRefs(globalScript));
diff --git a/layout/base/src/nsPresContext.h b/layout/base/src/nsPresContext.h
index ddf20d4038b..92f6cce13fb 100644
--- a/layout/base/src/nsPresContext.h
+++ b/layout/base/src/nsPresContext.h
@@ -262,7 +262,6 @@ protected:
   nsCOMPtr<nsIURI>      mBaseURL;
 
   nsCompatibility       mCompatibilityMode;
-  PRPackedBool          mCompatibilityLocked;
   nsWidgetRendering     mWidgetRenderingMode;
   PRPackedBool          mImageAnimationStopped;   // image animation stopped
 
diff --git a/layout/html/base/src/nsPresShell.cpp b/layout/html/base/src/nsPresShell.cpp
index 1f41cee5618..a5c4a9bff7d 100644
--- a/layout/html/base/src/nsPresShell.cpp
+++ b/layout/html/base/src/nsPresShell.cpp
@@ -1057,7 +1057,8 @@ public:
   NS_IMETHOD Init(nsIDocument* aDocument,
                   nsIPresContext* aPresContext,
                   nsIViewManager* aViewManager,
-                  nsIStyleSet* aStyleSet);
+                  nsIStyleSet* aStyleSet,
+                  PRBool aIsQuirksMode);
   NS_IMETHOD Destroy();
 
   NS_IMETHOD AllocateFrame(size_t aSize, void** aResult);
@@ -1678,7 +1679,8 @@ NS_IMETHODIMP
 PresShell::Init(nsIDocument* aDocument,
                 nsIPresContext* aPresContext,
                 nsIViewManager* aViewManager,
-                nsIStyleSet* aStyleSet)
+                nsIStyleSet* aStyleSet,
+                PRBool aIsQuirksMode)
 {
   NS_PRECONDITION(nsnull != aDocument, "null ptr");
   NS_PRECONDITION(nsnull != aPresContext, "null ptr");
@@ -1699,11 +1701,16 @@ PresShell::Init(nsIDocument* aDocument,
   mViewManager->SetViewObserver(this);
 
   // Bind the context to the presentation shell.
-  mPresContext = dont_QueryInterface(aPresContext);
+  mPresContext = aPresContext;
   aPresContext->SetShell(this);
 
   mStyleSet = aStyleSet;
 
+  // Set the compatibility mode after attaching the pres context and
+  // style set, but before creating any frames.
+  mPresContext->SetCompatibilityMode(aIsQuirksMode
+                         ? eCompatibility_NavQuirks : eCompatibility_Standard);
+
   mHistoryState = nsnull;
 
   nsresult result = nsComponentManager::CreateInstance(kFrameSelectionCID, nsnull,
diff --git a/layout/style/nsStyleSet.cpp b/layout/style/nsStyleSet.cpp
index dfdf41c317f..dfb535bf0a3 100644
--- a/layout/style/nsStyleSet.cpp
+++ b/layout/style/nsStyleSet.cpp
@@ -864,9 +864,23 @@ NS_IMETHODIMP StyleSetImpl::EnableQuirkStyleSheet(PRBool aEnable)
       }
     }
   }
+  NS_ASSERTION(mQuirkStyleSheet, "no quirk stylesheet");
   if (mQuirkStyleSheet) {
 #if defined(DEBUG_warren) || defined(DEBUG_attinasi)
     printf( "%s Quirk StyleSheet\n", aEnable ? "Enabling" : "Disabling" );
+#endif
+#ifdef DEBUG
+    PRUint32 count = 0;
+    if (mAgentRuleProcessors)
+      mAgentRuleProcessors->Count(&count);
+    PRBool enabledNow;
+    mQuirkStyleSheet->GetEnabled(enabledNow);
+    NS_ASSERTION(count == 0 || aEnable == enabledNow,
+                 "enabling/disabling quirk stylesheet too late");
+#ifdef DEBUG_dbaron
+    if (count != 0 && aEnable == enabledNow)
+      printf("WARNING: We set the quirks mode too many times.\n"); // we do!
+#endif
 #endif
     mQuirkStyleSheet->SetEnabled(aEnable);
   }