app/assets/javascripts/backbone-nested-attributes/undoable.js in backbone-nested-attributes-0.2.3 vs app/assets/javascripts/backbone-nested-attributes/undoable.js in backbone-nested-attributes-0.3.0

@@ -14,20 +14,37 @@
     change: function () {
       this.changed = true
     },
 
     save: function () {
-      this.attributes = this.model.toJSON()
-      this.changed = false
+      this.updateAttributes()
 
       this.model.trigger('state:store')
     },
 
     undo: function () {
+      this.attributesToUnset().each(function (attribute) {
+        this.model.unset(attribute)
+      }, this)
+
       this.model.set(this.attributes)
-      this.changed = false
 
+      this.updateAttributes()
+
       this.model.trigger('state:restore')
+    },
+
+    attributesToUnset: function () {
+      var previousAttributes = _(this.attributes || {}).keys()
+
+      return _(this.model.attributes).chain().keys().select(function (attribute) {
+        return !_(previousAttributes).include(attribute)
+      })
+    },
+
+    updateAttributes: function () {
+      this.attributes = this.model.toJSON({ withDeleted: true })
+      this.changed = false
     }
   })
 
   Backbone.UndoableModel = NestedAttributesModel.extend({
     initialize: function () {
\ No newline at end of file