diff --git a/mozilla/xpfe/components/regviewer/nsRegistryDataSource.cpp b/mozilla/xpfe/components/regviewer/nsRegistryDataSource.cpp
index 6f3e450aad6..9115b0493a0 100644
--- a/mozilla/xpfe/components/regviewer/nsRegistryDataSource.cpp
+++ b/mozilla/xpfe/components/regviewer/nsRegistryDataSource.cpp
@@ -195,7 +195,7 @@ nsRegistryDataSource::QueryInterface(const nsIID& aIID, void** aResult)
         return NS_NOINTERFACE;
     }
 
-    NS_ADDREF(NS_REINTERPRET_CAST(nsISupports*, this));
+    NS_ADDREF(NS_REINTERPRET_CAST(nsISupports*, *aResult));
     return NS_OK;
 }