A new installation of Thunderbird did not open hyperlinks in incoming mails. After ~3 days of looking for a fix, I found it in
AndrzejL's Re: Fixing Skype / Thunderbird / Google Earth connection with Firefox on PCLinuxOS-Forums. This is to publicise AndrzejL's technique because I had found it early in the search for a solution and dismissed it as similar to others and/or not closely related to the problem.
AIUI AndrzejL's technique applies when there are no entries for HTTP and...
