Selecting topics that are far down in the browse menu doesn't do anything. It seems to have something to do with them not being loaded, since it works if you have scrolled down to them first.
Steps to reproduce:
- Go to https://www.mediawiki.org/wiki/Talk:Wikimedia_Engineering_Architecture_Principles
- Click on "Browse topics"
- Select topic "Coverage"
The page scrolls down to the selected topic.
It works if you select multiple times, e.g. selecting "Coverage", then another topic, then "Coverage" again.
Using Firefox 66.0.5.