diff --git a/pvDataApp/pv/pvData.h b/pvDataApp/pv/pvData.h
index bfc5ed9..2ac0fb1 100644
--- a/pvDataApp/pv/pvData.h
+++ b/pvDataApp/pv/pvData.h
@@ -57,7 +57,7 @@ public:
 };
 
 class PVField
-: public Requester,
+: virtual public Requester,
   virtual public Serializable,
   private NoDefaultMethods
 {