diff --git a/mozilla/docshell/base/nsDocShell.cpp b/mozilla/docshell/base/nsDocShell.cpp
index e924d67ce91..0951005c2ab 100644
--- a/mozilla/docshell/base/nsDocShell.cpp
+++ b/mozilla/docshell/base/nsDocShell.cpp
@@ -2683,9 +2683,6 @@ NS_IMETHODIMP nsDocShell::SetupNewViewer(nsIContentViewer* aNewViewer)
    if (commandDispatcher)
      commandDispatcher->SetSuppressFocus(PR_FALSE);
 
-   if(mScriptContext)
-      mScriptContext->GC();
-
    mContentViewer = aNewViewer;
 
    nsCOMPtr<nsIWidget> widget;
diff --git a/mozilla/dom/src/base/nsGlobalWindow.cpp b/mozilla/dom/src/base/nsGlobalWindow.cpp
index a163c416d5e..5705e3ab33f 100644
--- a/mozilla/dom/src/base/nsGlobalWindow.cpp
+++ b/mozilla/dom/src/base/nsGlobalWindow.cpp
@@ -269,7 +269,9 @@ NS_IMETHODIMP GlobalWindowImpl::SetNewDocument(nsIDOMDocument* aDocument)
                                    (JSObject *) mScriptObject);
 
   if (mFirstDocumentLoad) {
-    mFirstDocumentLoad = PR_FALSE;
+    if (aDocument)
+      mFirstDocumentLoad = PR_FALSE;
+
     mDocument = aDocument;
     return NS_OK;
   }
@@ -321,7 +323,7 @@ NS_IMETHODIMP GlobalWindowImpl::SetNewDocument(nsIDOMDocument* aDocument)
     mDocument = nsnull;         // Forces Release
   }
 
-  if (mContext) {
+  if (mContext && aDocument) {
     // Add an extra ref in case we release mContext during GC.
     nsCOMPtr<nsIScriptContext> kungFuDeathGrip = mContext;
     kungFuDeathGrip->GC();