Gene

Screen shot - sure - I don't have the firefox version.  

If I chenge TB color settings to never override - then the preferences work fine. However the preview pane in TB now has white background which is horrible for dark...

Also, just in case this be helpful, I have 2 other addons and they both work fine (cardbook and dkim-verifier)

In thunderbird : settings -> language & appearence -> colors In the popup window there is a drop down as shown here: 

Thanks for doing research / follow up. The option to use OS theme makes no difference - starting to seem like this may well be bug with TB - for...

cool thanks!

Seems its a known bug https://bugzilla.mozilla.org/show_bug.cgi?id=1690531 @tdulcet give your detailed understanding how TB works, it would be helpful if you added your thoughts to the bugzilla? thanks

Please be careful with key size, by itself its not a good marker of security. ECC is part of the 2017 DKIM draft[1] and ECC key lengths are way shorter...

While this has worked surprisingly well for a moribund project its probably time for a active alternative ?

I believe the original poster here has since gone on to work on dkimpy tools. Dan I understand your openssl comment - though there is libsodium with good support of...