null异常

列表有个按钮，按钮点击事件移除当前界面
Uncaught TypeError: Cannot read property 'event' of null
at Function.t.dispatch (fairygui.min.js:1)
at t.e.refresh (fairygui.min.js:3)
at LaterHandler.__proto.run (laya.core.js:10366)
at CallLater.__proto._update (laya.core.js:10289)
at Stage.__proto.render (laya.core.js:21645)
at Stage.__proto._loop (laya.core.js:21598)
at loop (laya.core.js:7950)