Rated 5 out of 5 stars

by turbodent on ژانویه 29, 2021 ·

I used to LOVE this when it worked, thanks to the author for all these good years... :)
For those interested in a similar solution, you may want to look into BorderColors D
https://addons.thunderbird.net/en-GB/thunderbird/addon/bordercolors-d/?src=search