Roman can you check out the following link? https://www.suchan.me/sonnensegel
The toc plugin seems to work pretty fine, but i have an strange issue with firefox and accrodion elements on that page. However it works prefectly smooth with chrome. Probably you can figure out what is going wrong.
An another "issue" with toc plugin is, that the custom css and java script things are only visible after saving if you marc the content. If you save and go out of extension or widget settings and come back you will see a blanc screen.