A while ago, I posted a modified version of this widget. Since then, I made some corrections to fix some bugs and implemented some enhancements. With this version you can save in the session a local file (shapefile), in addition to any web service based layers, and the basemap that you are using. This version was developed in version 2.4 and it was tested in Chrome and IE. Just add this widget in the widget folder in your app and add the entry in the config.json.