diff --git a/layout/generic/nsObjectFrame.cpp b/layout/generic/nsObjectFrame.cpp
index 8e8368f0934c..2a77576ca555 100644
--- a/layout/generic/nsObjectFrame.cpp
+++ b/layout/generic/nsObjectFrame.cpp
@@ -2403,6 +2403,14 @@ nsPluginInstanceOwner::nsPluginInstanceOwner()
   mPluginScale = 1.0;
   mSharedXImage = nsnull;
   mSharedSegmentInfo.shmaddr = nsnull;
+#endif
+
+#ifdef XP_MACOSX
+#ifndef NP_NO_QUICKDRAW
+  mEventModel = NPEventModelCarbon;
+#else
+  mEventModel = NPEventModelCocoa;
+#endif
 #endif
   PR_LOG(nsObjectFrameLM, PR_LOG_DEBUG,
          ("nsPluginInstanceOwner %p created\n", this));