[opensuse] Opening links from email - what browser?

Hi, Seeing that my Firefox was bloated with a large number of tabs, I created a new FF profile and started fresh, with just a few tabs. Fine. But there is a nuisance: I can not click on links in email (Thunderbird and others): they insist in opening the full "Default" FF profile with a ton of windows and tabs, instead of opening a new tab in the already running FF instance. How can I change that? XFCE, Leap 15.0 -- Cheers / Saludos, Carlos E. R. (from 15.0 x86_64 at Telcontar)