diff --git a/js/src/xpconnect/src/xpcconvert.cpp b/js/src/xpconnect/src/xpcconvert.cpp
index 2adc4a93acf2..dd088d9339e4 100644
--- a/js/src/xpconnect/src/xpcconvert.cpp
+++ b/js/src/xpconnect/src/xpcconvert.cpp
@@ -827,35 +827,42 @@ XPCConvert::JSObject2NativeInterface(XPCCallContext& ccx,
 
     nsISupports* iface;
 
-    // is this really a native xpcom object with a wrapper?
-    XPCWrappedNative* wrappedNative =
-                XPCWrappedNative::GetWrappedNativeOfJSObject(cx, src);
-    if(wrappedNative)
+
+    if(!aOuter)
     {
-        iface = wrappedNative->GetIdentityObject();
-        // is the underlying object the right interface?
-        if(wrappedNative->GetIID().Equals(*iid))
+        // Note that if we have a non-null aOuter then it means that we are
+        // forcing the creation of a wrapper even if the object *is* a 
+        // wrappedNative or other wise has 'nsISupportness'. 
+        // This allows wrapJSAggregatedToNative to work.
+
+        // Is this really a native xpcom object with a wrapper?
+        XPCWrappedNative* wrappedNative =
+                    XPCWrappedNative::GetWrappedNativeOfJSObject(cx, src);
+        if(wrappedNative)
         {
-            NS_ADDREF(iface);
-            *dest = iface;
-            return JS_TRUE;
+            iface = wrappedNative->GetIdentityObject();
+            // is the underlying object the right interface?
+            if(wrappedNative->GetIID().Equals(*iid))
+            {
+                NS_ADDREF(iface);
+                *dest = iface;
+                return JS_TRUE;
+            }
+            else
+                return NS_SUCCEEDED(iface->QueryInterface(*iid, dest));
+        }
+        // else...
+        
+        // Does the JSObject have 'nsISupportness'?
+        // XXX hmm, I wonder if this matters anymore with no 
+        // oldstyle DOM objects around.
+        if(GetISupportsFromJSObject(cx, src, &iface))
+        {
+            if(iface)
+                return NS_SUCCEEDED(iface->QueryInterface(*iid, dest));
+            return JS_FALSE;
+        
         }
-        else
-            return NS_SUCCEEDED(iface->QueryInterface(*iid, dest));
-    }
-    // else...
-
-    // Does the JSObject have 'nsISupportness'? (as do DOM objects.)
-    // Note that if we have a non-null aOuter then it means that we are
-    // forcing the creation of a wrapper even if the object *does* have
-    // 'nsISupportness'. This allows wrapJSAggregatedToNative to work
-    // with JSObjects that happen to have 'nsISupportness'.
-    if(!aOuter && GetISupportsFromJSObject(cx, src, &iface))
-    {
-        if(iface)
-            return NS_SUCCEEDED(iface->QueryInterface(*iid, dest));
-        return JS_FALSE;
-
     }
 
     // else...
diff --git a/js/src/xpconnect/src/xpcprivate.h b/js/src/xpconnect/src/xpcprivate.h
index 9b9ed729c4be..596215727a91 100644
--- a/js/src/xpconnect/src/xpcprivate.h
+++ b/js/src/xpconnect/src/xpcprivate.h
@@ -2505,6 +2505,13 @@ public:
     void ClearRecentContext()
         {mMostRecentJSContext = nsnull; mMostRecentXPCContext = nsnull;}
 
+#ifdef XPC_CHECK_WRAPPER_THREADSAFETY
+    JSUint32  IncrementWrappedNativeThreadsafetyReportDepth()
+        {return ++mWrappedNativeThreadsafetyReportDepth;}
+    void      ClearWrappedNativeThreadsafetyReportDepth()
+        {mWrappedNativeThreadsafetyReportDepth = 0;}
+#endif
+
 private:
     XPCPerThreadData();
 
@@ -2521,6 +2528,9 @@ private:
     nsIExceptionManager* mExceptionManager;
     nsIException*        mException;
     JSBool               mExceptionManagerNotAvailable;
+#ifdef XPC_CHECK_WRAPPER_THREADSAFETY
+    JSUint32             mWrappedNativeThreadsafetyReportDepth;
+#endif
 
     static PRLock*           gLock;
     static XPCPerThreadData* gThreads;
diff --git a/js/src/xpconnect/src/xpcthreadcontext.cpp b/js/src/xpconnect/src/xpcthreadcontext.cpp
index ba1979d36a35..ed0dd6609c3f 100644
--- a/js/src/xpconnect/src/xpcthreadcontext.cpp
+++ b/js/src/xpconnect/src/xpcthreadcontext.cpp
@@ -347,7 +347,9 @@ XPCPerThreadData::XPCPerThreadData()
         mExceptionManager(nsnull),
         mException(nsnull),
         mExceptionManagerNotAvailable(JS_FALSE)
-
+#ifdef XPC_CHECK_WRAPPER_THREADSAFETY
+      , mWrappedNativeThreadsafetyReportDepth(0)
+#endif
 {
     if(gLock)
     {
diff --git a/js/src/xpconnect/src/xpcwrappednative.cpp b/js/src/xpconnect/src/xpcwrappednative.cpp
index 42178632700d..5bdc5e850426 100644
--- a/js/src/xpconnect/src/xpcwrappednative.cpp
+++ b/js/src/xpconnect/src/xpcwrappednative.cpp
@@ -781,10 +781,10 @@ XPCWrappedNative::AddRef(void)
     NS_LOG_ADDREF(this, cnt, "XPCWrappedNative", sizeof(*this));
     if(2 == cnt && IsValid())
     {
-        XPCCallContext ccx(NATIVE_CALLER);
-        if(ccx.IsValid())
-            JS_AddNamedRoot(ccx, &mFlatJSObject,
-                            "XPCWrappedNative::mFlatJSObject");
+        XPCJSRuntime* rt = GetRuntime();
+        if(rt)
+            JS_AddNamedRootRT(rt->GetJSRuntime(), &mFlatJSObject,
+                              "XPCWrappedNative::mFlatJSObject");
     }
     return cnt;
 }
@@ -2671,6 +2671,10 @@ void DEBUG_ReportWrapperThreadSafetyError(XPCCallContext& ccx,
                                           const char* msg,
                                           const XPCWrappedNative* wrapper)
 {
+    XPCPerThreadData* tls = ccx.GetThreadData();
+    if(1 != tls->IncrementWrappedNativeThreadsafetyReportDepth())
+        return;
+
     printf("---------------------------------------------------------------\n");
     printf("!!!!! XPConnect wrapper thread use error...\n");
 
@@ -2686,7 +2690,8 @@ void DEBUG_ReportWrapperThreadSafetyError(XPCCallContext& ccx,
     printf("  JS call stack...\n");
     xpc_DumpJSStack(ccx, JS_TRUE, JS_TRUE, JS_TRUE);
     printf("---------------------------------------------------------------\n");
-
+    
+    tls->ClearWrappedNativeThreadsafetyReportDepth();
 }
 
 void DEBUG_CheckWrapperThreadSafety(const XPCWrappedNative* wrapper)
@@ -2710,8 +2715,9 @@ void DEBUG_CheckWrapperThreadSafety(const XPCWrappedNative* wrapper)
     {
         XPCCallContext ccx(NATIVE_CALLER);
         DEBUG_ReportWrapperThreadSafetyError(ccx,
-            "Wrapper accessed on multiple threads without having an "
-            "nsIClassInfo that set the 'THREADSAFE' flag", wrapper);
+            "XPConnect WrappedNative is being accessed on multiple threads but "
+            "the underlying native xpcom object does not have a "
+            "nsIClassInfo with the 'THREADSAFE' flag set", wrapper);
     }
 }
 #endif