From your text, it sounds like you did in fact read the documentation, but are having some graphical issues with the configuration screen, is that correct? I would initially suggest looking at your windows DPI settings. Try setting that to 100%. If you already have that, or the problem still occurs, Please file a support ticket including a screenshot of the issue and a test project.
With regards to the demo project, I don't think it's currently compatible with Mendix 5. It's not marked as such, and the actual widget has been separated from the grid view into a mendix 5 compatible version (treeview).