My "Settings/Preferred Application" is set to Evolution, yet when there is an email link in a web page Thunderbird is activated. I did some Internet research but could not find solution. I do not have 'Activities/Details' menu or similar. This is xubuntu 18.04 with Firefox as web browser and Evolution as email client. I abandoned Thunderbird because Lightning started to loose home calendar and I had to remove and re-install Lightning. Fortunately, my calendar entries were still there.
Change the preference in Firefox. type
about:preferences
in the address bar and scroll down. Then typemail
in the box.I don't have Evolution installed so I can't show exactly how to do it, but when you click on
Use Thunderbird Mail (default)
you will get a dropdown menu with other choices. Hopefully Evolution will be one of the choices.