     super
 
     @emitter = new Emitter
+    @subscriptions = new CompositeDisposable
     @items = []
 
     @addItems(compact(params?.items ? []))

  addItem: (item, index=@getActiveItemIndex() + 1) ->
    return if item in @items

    if typeof item.on is 'function'
      @subscribe item, 'destroyed', => @removeItem(item, true)


{find, compact, extend, last} = require 'underscore-plus'
{Model} = require 'theorist'
{CompositeDisposable, Emitter} = require 'event-kit'
Serializable = require 'serializable'
Grim = require 'grim'
PaneAxis = require './pane-axis'
