For example this page, https://yle.fi/a/3-11868513 , causes my Firefox to go unresponsive for maybe 10-20 seconds at a time, when scrolling up and down. Windows works fine. It's not the only one, I have found some other on that same news site, which use the same kind of construct for a page that contains both video and text. When I open Firefox in troubleshooting mode, page works fine. But in normal mode, even if I disable all my extensions (except search engines), page still hangs. On the other hand, I haven't encountered this kind of behaviour in normal mode in any other pages or sites. So it may be something very spesific that site uses on those particular pages. So it is a minor problem but because disabling all extensions did not help, I thought it might be worth bringing up.