diff --git a/dom/src/base/nsJSEnvironment.cpp b/dom/src/base/nsJSEnvironment.cpp
index 208c661f3ade..6408eccc8376 100644
--- a/dom/src/base/nsJSEnvironment.cpp
+++ b/dom/src/base/nsJSEnvironment.cpp
@@ -2313,9 +2313,10 @@ nsJSContext::ConnectToInner(nsIScriptGlobalObject *aNewInner, void *aOuterGlobal
   JSObject *newInnerJSObject = (JSObject *)aNewInner->GetScriptGlobal(JAVASCRIPT);
   JSObject *myobject = (JSObject *)aOuterGlobal;
 
-  // *Don't* call JS_ClearScope here since it's unnecessary
-  // and it confuses the JS engine as to which Function is
-  // on which window. See bug 343966.
+  // Call ClearScope to nuke any properties (e.g. Function and Object) on the
+  // outer object. From now on, anybody asking the outer object for these
+  // properties will be forwarded to the inner window.
+  ::JS_ClearScope(mContext, myobject);
 
   // Make the inner and outer window both share the same
   // prototype. The prototype we share is the outer window's
diff --git a/js/src/xpconnect/src/nsXPConnect.cpp b/js/src/xpconnect/src/nsXPConnect.cpp
index dd1db9bcc7a1..99997ebc06b7 100644
--- a/js/src/xpconnect/src/nsXPConnect.cpp
+++ b/js/src/xpconnect/src/nsXPConnect.cpp
@@ -1067,7 +1067,7 @@ TempGlobalResolve(JSContext *aJSContext, JSObject *obj, jsval id)
 }
 
 static JSClass xpcTempGlobalClass = {
-    "xpcTempGlobalClass", 0,
+    "xpcTempGlobalClass", JSCLASS_GLOBAL_FLAGS,
     JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,
     JS_EnumerateStub, TempGlobalResolve, JS_ConvertStub,   JS_FinalizeStub,
     JSCLASS_NO_OPTIONAL_MEMBERS