I would love to see Thunderbird incorporate a way to color the customized colors. I had used an add-on and had all my projects in color-coded folders by location - green for one county, red for another, etc. - and each order, when completed, had been placed in its own folder, which I had color-coded. With the new update, all my colors disappeared again. That's about 1,000 folders that I will have to go back and manually color.