Rated 4 out of 5 stars

Hello,
Thanks for your reply. I uninstalled the extension, relaunched TB, reinstalled the extension; clicking on a link opens the browser, not a tab in TB.
I have the same problem with Dark Reader, which doesn't work since the last update (macOS 13.5.1).
Best regards
Lise

This review is for a previous version of the add-on (1.6). 

Hello again,
Now I remember, there have been reports like this some years ago and it was never fixed so it probably still exists. Somehow Thunderbird can break addons during the update and even reinstalling doesn't help (because the issue is in some kind of startup-cache). Maybe if you uninstall it for a week and then try to install it back, it could help (who knows how long it takes for the startup cache to clear).
Here is the link for the original issue:
https://bugzilla.mozilla.org/show_bug.cgi?id=1707573

Best Regards,
Juraj Mäsiar

Rated 4 out of 5 stars

Great extension that worked very well up to TB 115 but no longer works with version TB 115.2.0

This review is for a previous version of the add-on (1.6). 

Hello,
It should work even after the update, at least it works here.
Try to uninstall it, restart Thunderbird and install it back. That could fix the issue.
Best Regards,
Juraj Mäsiar