Language Selector / jquery


I just downloaded grav, started the docker-container, unzipped a skeleton, installed the admin panel and was immediately pleased with the results. Looks modern, shiny and yet manageable, perfectly suited for the task at hand, which is to build a small and simple company website.
The skeleton I used is x-corporation, but unfortunately I need multilanguage support, so I downloaded the language-selector plugin by clemdesign.
This is where I am stuck now, I can add the plugin to the navbar just fine, but I cannot get the thing to display its dropdown menu, I think I did the configuration correctly, though.
How can I check wether jquery is working as it is supposed to? Do I need to do anything else than include the twig partial?

Best regards,