Thunderbird and preferred applications

[Ralf Mardorf]

On Mon, 1 Oct 2018 11:02:10 +0200, Paul Menzel wrote:
>Is it a Mozilla Thunderbird problem, that it opens a different browser
>than is configured under Settings → Preferred Applications?

I don't know, since I do not use Thunderbird, so lets take a look:

http://lmgtfy.com/?q=thunderbird+browser

Third hit:

Changing the web browser invoked by Thunderbird - MozillaZine ...
http://kb.mozillazine.org/Changing_the_web_browser_invoked_by_Thunderbird