Reader Chuck recently asked about enhancing new labels for Thunderbird:

I’ve been trying to figure out how to change some of this stuff for a long time. My one question though – how do you change the label backgrounds for additional labels you have added(other than the default 5 that come with Thunderbird).

I realized that this is probably more common than one might think. So I’m going to share my answer with all of you.

This customization goes back to Personalizing Thunderbird’s chrome, but note that you can also do this with the Stylish Add-on for Thunderbird. In this case it’s not necessary to dig into your userChrome.css file, but if you want to than here are instructions.

It’s been awhile since we tweaked our Firefox chrome, and it’s about time we get to hack Mozilla’s wonderful email client Thunderbird.

In this post I’ll give you the necessary tools to change the look of Thunderbird and give you some suggestions (and code, of course :) to help you along the way. First, let me give credit to Twister MC’s wonderful post that I will be using as a reference for the label coloring scripts below. OK, let’s get started!