The problem is with apps that send mail as 'rich text', such as some mobile mail apps: a link that is entered directly as https://support.mozilla.org/en-US/questions/1321403 is not clickable when received in TB Original HTML, whereas an embedded link is clickable. Try it by sending a message with the W10 Mail app and reading it in TB.

I don't think there's any way to make these links clickable in Original or Simple HTML, but switching between the different views is made easier with Toggle HTML.

Thanks for the reply.

The Toggle HTML add-on is a good workaround, though its permission for "full unrestricted access to your computer" is a little unnerving.

Is there a place I can suggest a new feature for Thunderbird that would make plain-text links clickable no matter what the viewing format?

-- oobleck

The 'full access' caveat is standard boilerplate now with all add-ons, and doesn't imply any higher level of access than TB itself.

Requests For Enhancement may be submitted at Bugzilla.

Thanks, from what I googled it sounded like that was the case.

-- oobleck