I vaguely remembered that and it had to do with Thunderbird’s apparmor profile. See if this forum link helps your problem.
Personally, I do not like links opening automatically. I am afraid I’ll screw up. 
Otherwise, I would check for you.
I vaguely remembered that and it had to do with Thunderbird’s apparmor profile. See if this forum link helps your problem.
Personally, I do not like links opening automatically. I am afraid I’ll screw up. Otherwise, I would check for you.