diff --git a/src/as/com/threerings/presents/dobj/ElementUpdatedEvent.as b/src/as/com/threerings/presents/dobj/ElementUpdatedEvent.as
index d3bddc8cf..59c5246de 100644
--- a/src/as/com/threerings/presents/dobj/ElementUpdatedEvent.as
+++ b/src/as/com/threerings/presents/dobj/ElementUpdatedEvent.as
@@ -30,12 +30,14 @@ public class ElementUpdatedEvent extends NamedEvent
      * @param index the index in the array of the updated element.
      */
     public function ElementUpdatedEvent (
-        targetOid :int, name :String, value :Object, oldValue :Object,
-        index :int)
+            targetOid :int = 0, name :String = null, value :Object = null,
+            oldValue :Object = null, index :int = 0)
     {
         super(targetOid, name);
         _value = value;
-        _oldValue = oldValue;
+        if (oldValue != null) {
+            _oldValue = oldValue;
+        }
         _index = index;
     }
 
diff --git a/src/as/com/threerings/presents/dobj/InvocationNotificationEvent.as b/src/as/com/threerings/presents/dobj/InvocationNotificationEvent.as
index 01bbf6785..03b8c755a 100644
--- a/src/as/com/threerings/presents/dobj/InvocationNotificationEvent.as
+++ b/src/as/com/threerings/presents/dobj/InvocationNotificationEvent.as
@@ -48,7 +48,8 @@ public class InvocationNotificationEvent extends DEvent
      * only values of valid distributed object types.
      */
     public function InvocationNotificationEvent (
-        targetOid :int, receiverId :int, methodId :int, args :Array)
+        targetOid :int = 0, receiverId :int = 0, methodId :int = 0,
+        args :Array = null)
     {
         super(targetOid);
         _receiverId = receiverId;
diff --git a/src/as/com/threerings/presents/dobj/InvocationRequestEvent.as b/src/as/com/threerings/presents/dobj/InvocationRequestEvent.as
index b47946952..f8970c104 100644
--- a/src/as/com/threerings/presents/dobj/InvocationRequestEvent.as
+++ b/src/as/com/threerings/presents/dobj/InvocationRequestEvent.as
@@ -45,7 +45,8 @@ public class InvocationRequestEvent extends DEvent
      * only values of valid distributed object types.
      */
     public function InvocationRequestEvent (
-        targetOid :int, invCode :int, methodId :int, args :Array)
+            targetOid :int = 0, invCode :int = 0, methodId :int = 0,
+            args :Array = null)
     {
         super(targetOid);
         _invCode = invCode;
diff --git a/src/as/com/threerings/presents/dobj/InvocationResponseEvent.as b/src/as/com/threerings/presents/dobj/InvocationResponseEvent.as
index 7fe2e9910..9af9bd7bb 100644
--- a/src/as/com/threerings/presents/dobj/InvocationResponseEvent.as
+++ b/src/as/com/threerings/presents/dobj/InvocationResponseEvent.as
@@ -45,8 +45,8 @@ public class InvocationResponseEvent extends DEvent
      * only values of valid distributed object types.
      */
     public function InvocationResponseEvent (
-        targetOid :int = 0, requestId :int = 0, methodId :int = 0,
-        args :Array = null)
+            targetOid :int = 0, requestId :int = 0, methodId :int = 0,
+            args :Array = null)
     {
         super(targetOid);
         _requestId = requestId;
diff --git a/src/as/com/threerings/presents/dobj/ObjectAddedEvent.as b/src/as/com/threerings/presents/dobj/ObjectAddedEvent.as
index 2d3c8a88d..4a6e75706 100644
--- a/src/as/com/threerings/presents/dobj/ObjectAddedEvent.as
+++ b/src/as/com/threerings/presents/dobj/ObjectAddedEvent.as
@@ -25,7 +25,8 @@ public class ObjectAddedEvent extends NamedEvent
      * the specified oid.
      * @param oid the oid to add to the oid list attribute.
      */
-    public function ObjectAddedEvent (targetOid :int, name :String, oid :int)
+    public function ObjectAddedEvent (
+            targetOid :int = 0, name :String = null, oid :int = 0)
     {
         super(targetOid, name);
         _oid = oid;
@@ -54,7 +55,7 @@ public class ObjectAddedEvent extends NamedEvent
     protected override function notifyListener (listener :Object) :void
     {
         if (listener is OidListListener) {
-            listener.objectAdded(this);
+            (listener as OidListListener).objectAdded(this);
         }
     }
 
diff --git a/src/as/com/threerings/presents/dobj/ObjectDestroyedEvent.as b/src/as/com/threerings/presents/dobj/ObjectDestroyedEvent.as
index 1c5024bf5..9d42e5d57 100644
--- a/src/as/com/threerings/presents/dobj/ObjectDestroyedEvent.as
+++ b/src/as/com/threerings/presents/dobj/ObjectDestroyedEvent.as
@@ -38,7 +38,7 @@ public class ObjectDestroyedEvent extends DEvent
      *
      * @param targetOid the object id of the object that will be destroyed.
      */
-    public function ObjectDestroyedEvent (targetOid :int)
+    public function ObjectDestroyedEvent (targetOid :int = 0)
     {
         super(targetOid);
     }