diff --git a/mozilla/xpcom/proxy/src/nsProxyObjectManager.cpp b/mozilla/xpcom/proxy/src/nsProxyObjectManager.cpp
index d29a53925d3..3d7ba2c6dda 100644
--- a/mozilla/xpcom/proxy/src/nsProxyObjectManager.cpp
+++ b/mozilla/xpcom/proxy/src/nsProxyObjectManager.cpp
@@ -265,6 +265,7 @@ nsProxyObjectManager::GetClass(REFNSIID aIID, nsProxyEventClass **aResult)
     if (mProxyClassMap.Get(aIID, aResult)) {
         NS_ASSERTION(*aResult, "Null data in mProxyClassMap");
         delete pec;
+        return NS_OK;
     }
 
     if (!mProxyClassMap.Put(aIID, pec)) {