In 5.1.9 this is not included so you cannot edit module files on the dashboard.

Add the folder jquery.fileTree in asset->plugins->bower_components
Then replace the following code in two files:
views/sximo/code/index.blade.php and 
views/sximo/module/code/code.blade.php
<pre>
	<!-- N.R. jqueryFileTree fix -->
	<script type="text/javascript" src="{{ asset('assets/plugins/bower_components/jquery.fileTree/jqueryFileTree.js') }}"></script>
	<link href="{{ asset('assets/plugins/bower_components/jquery.fileTree/jqueryFileTree.css') }}" rel="stylesheet">
	<!-- end -->
</pre>