diff --git a/mozilla/content/html/document/src/nsPluginDocument.cpp b/mozilla/content/html/document/src/nsPluginDocument.cpp
index 5d2d1d1fd56..0a88515a733 100644
--- a/mozilla/content/html/document/src/nsPluginDocument.cpp
+++ b/mozilla/content/html/document/src/nsPluginDocument.cpp
@@ -153,22 +153,11 @@ NS_IMPL_ISUPPORTS_INHERITED1(nsPluginDocument, nsMediaDocument,
 void
 nsPluginDocument::SetScriptGlobalObject(nsIScriptGlobalObject* aScriptGlobalObject)
 {
-  // Set the script global object on the superclass before doing
-  // anything that might require it....
-  nsMediaDocument::SetScriptGlobalObject(aScriptGlobalObject);
-
-  if (aScriptGlobalObject) {
-    if (!mPluginContent) {
-      // Create synthetic document
-#ifdef DEBUG
-      nsresult rv =
-#endif
-        CreateSyntheticPluginDocument();
-      NS_ASSERTION(NS_SUCCEEDED(rv), "failed to create synthetic document");
-    }
-  } else {
+  if (!aScriptGlobalObject) {
     mStreamListener = nsnull;
   }
+
+  nsMediaDocument::SetScriptGlobalObject(aScriptGlobalObject);
 }
 
 
@@ -190,17 +179,6 @@ nsPluginDocument::StartDocumentLoad(const char*         aCommand,
                                     PRBool              aReset,
                                     nsIContentSink*     aSink)
 {
-  // do not allow message panes to host full-page plugins
-  // returning an error causes helper apps to take over
-  nsCOMPtr<nsIDocShellTreeItem> dsti (do_QueryInterface(aContainer));
-  if (dsti) {
-    PRBool isMsgPane = PR_FALSE;
-    dsti->NameEquals(NS_LITERAL_STRING("messagepane").get(), &isMsgPane);
-    if (isMsgPane) {
-      return NS_ERROR_FAILURE;
-    }
-  }
-
   nsresult rv =
     nsMediaDocument::StartDocumentLoad(aCommand, aChannel, aLoadGroup,
                                        aContainer, aDocListener, aReset,
@@ -214,6 +192,12 @@ nsPluginDocument::StartDocumentLoad(const char*         aCommand,
     return rv;
   }
 
+  // Create synthetic document
+  rv = CreateSyntheticPluginDocument();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
   mStreamListener = new nsPluginStreamListener(this);
   if (!mStreamListener) {
     return NS_ERROR_OUT_OF_MEMORY;
@@ -227,8 +211,16 @@ nsPluginDocument::StartDocumentLoad(const char*         aCommand,
 nsresult
 nsPluginDocument::CreateSyntheticPluginDocument()
 {
-  NS_ASSERTION(!GetPrimaryShell() || !GetPrimaryShell()->DidInitialReflow(),
-               "Creating synthetic plugin document content too late");
+  // do not allow message panes to host full-page plugins
+  // returning an error causes helper apps to take over
+  nsCOMPtr<nsIDocShellTreeItem> dsti (do_QueryReferent(mDocumentContainer));
+  if (dsti) {
+    PRBool isMsgPane = PR_FALSE;
+    dsti->NameEquals(NS_LITERAL_STRING("messagepane").get(), &isMsgPane);
+    if (isMsgPane) {
+      return NS_ERROR_FAILURE;
+    }
+  }
 
   // make our generic document
   nsresult rv = nsMediaDocument::CreateSyntheticDocument();