open link from mail in browser, without switching to the browser

I just tried some of those tips, but they didn't work in my environment:

https://www.reddit.com/r/Thunderbird/comments/7amm15/open_links_in_background/

The config editor in Thunderbird is now in Edit -> Preferences -> first tab "General"; scroll all the way down and click on "Config Editor".

Maybe you are luckier than me with any of those tips from Reddit.