1 files changed, 1 insertions, 0 deletions

diff --git a/node_modules/montage/core/event/mutable-event.js b/node_modules/montage/core/event/mutable-event.js
index f94ee0b9..6f6a0cfd 100755
--- a/node_modules/montage/core/event/mutable-event.js
+++ b/node_modules/montage/core/event/mutable-event.js
@@ -105,6 +105,7 @@ var MutableEvent = exports.MutableEvent = Montage.create(Montage,/** @lends modu
             var changeEvent = new _changeEventConstructor();
             changeEvent.type = "change@" + key;
             changeEvent.minus = minus;
+            changeEvent.plus = undefined;
             changeEvent.propertyChange = ChangeTypes.MODIFICATION;
             return changeEvent;
         }