Trying to replicate part of the Admin Demo App

I am desperately trying to replicate the look and feel of the sidebar menu on the webix admin demo. I learned a lot about like all the parts of the framework and totally feel that this view is based on a template that allows it to be displayed that way, but I can’t find the actual template that is used for that and how it comes into play. Please some hint into the right direction would be nice, I really just want to understand :). If I try it I always get the +/- open close things and a checkbox and everything on it. I KNOW i can set it via a template and I already tried that and it was better, but I would really like to understand why it is displayed that way on the demo app.

Thanks in advance for any pointer on this topic.

This tree was created before a separate SideBar, so perhaps this component can be a handier solution.

However, this tree has a custom type which extends the plain CSS styling. The sources/demo you will find at the similar topic.

It is not about the CSS style, it is more about that it uses the icon and all, the template itself, in which exact line is that template set that is used, cause i CANT find it. That drives me crazy, cause I do not know why he displays it with icon if there is no actual command to do so, but I ran the demo on my local PC so i know it MUST BE in there, but its not. Also at the type there is no template defined, that is all making it so confusing, but i will look into the sidebar component, thanks for that.