diff --git a/mozilla/modules/plugin/base/src/nsJSNPRuntime.cpp b/mozilla/modules/plugin/base/src/nsJSNPRuntime.cpp
index 7f2280d07c6..e348e22da4a 100644
--- a/mozilla/modules/plugin/base/src/nsJSNPRuntime.cpp
+++ b/mozilla/modules/plugin/base/src/nsJSNPRuntime.cpp
@@ -835,22 +835,22 @@ nsJSObjWrapper::NP_RemoveProperty(NPObject *npobj, NPIdentifier identifier)
   AutoCXPusher pusher(cx);
   JSAutoRequest ar(cx);
   AutoJSExceptionReporter reporter(cx);
+  jsval deleted = JSVAL_FALSE;
 
   if (JSVAL_IS_STRING(id)) {
     JSString *str = JSVAL_TO_STRING(id);
 
-    jsval unused;
     ok = ::JS_DeleteUCProperty2(cx, npjsobj->mJSObj, ::JS_GetStringChars(str),
-                                ::JS_GetStringLength(str), &unused);
+                                ::JS_GetStringLength(str), &deleted);
   } else {
     NS_ASSERTION(JSVAL_IS_INT(id), "id must be either string or int!\n");
 
-    ok = ::JS_DeleteElement(cx, npjsobj->mJSObj, JSVAL_TO_INT(id));
+    ok = ::JS_DeleteElement2(cx, npjsobj->mJSObj, JSVAL_TO_INT(id), &deleted);
   }
 
   // return ok == JS_TRUE to quiet down compiler warning, even if
   // return ok is what we really want.
-  return ok == JS_TRUE;
+  return ok == JS_TRUE && deleted == JSVAL_TRUE;
 }
 
 //static