I have created a custom section in the backoffice following this article. It has a content tree in the left panel and a right panel with the relevant controls for my functionality. It looks like this when I have clicked on a node in the content tree:

Now, I would like the right pane to show the same controls after just entering the section and if I click on the top level "header" that reads "CONTENT FOR XML IMPORT". What happens now is that the right pane is just left blank like this:

Any backoffice extension experts that could help me out on this? I have tried to fiddle with the api controller and tree controller .cs and .js files, but - being a backoffice programming newbie - my understanding of the angular umbraco framework is insufficient.