       $container.append(prop.$el)
       return prop
 
-    addTweenProperty: (instance_prop, lineData, key_val, $container) =>
+    addTweenProperty: (instance_prop, lineData, key_val, $container, propertyData, domElement) =>
       tween = new PropertyTween(instance_prop, lineData, @editor, key_val, @timeline)
       $container.append(tween.$el)
 

        index = propertyData.keys.indexOf(key_val)
        if index > -1
          propertyData.keys.splice(index, 1)
          @keyRemoved.dispatch(domElement)
          lineData._isDirty = true
      return tween



      if property_name
        # Add tween select if we are editing a key.
        tweenProp = @addTweenProperty(instance_prop, lineData, key_val, $container, propertyData, domElement)
        @items.push(tweenProp)

      return
