Enable file browser extension.

jupyterlab/index.js

@@ -19,7 +19,7 @@ lab.registerPlugins([
   require('jupyterlab/lib/docregistry/plugin').docRegistryProvider,
   // require('jupyterlab/lib/editorwidget/plugin').editorHandlerExtension,
   // require('jupyterlab/lib/faq/plugin').faqExtension,
-  // require('jupyterlab/lib/filebrowser/plugin').fileBrowserProvider,
+  require('jupyterlab/lib/filebrowser/plugin').fileBrowserProvider,
   // require('jupyterlab/lib/help/plugin').helpHandlerExtension,
   // require('jupyterlab/lib/imagewidget/plugin').imageHandlerExtension,
   // require('jupyterlab/lib/inspector/plugin').inspectorExtension,