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My userChrome.css for Thunderbird

Last modified:
363 Words
01:33 | by AlexVie
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This is probably outdated by now. It’s been written for Thunderbird 52 which is no longer the most recent version. Thunderbird 60, the successor which is currently in Beta, requires minor changes to the userChrome stuff listed here. It will be updated when it goes final.

I have written an article about Thunderbird 60 here

Even though there are many alternatives today, I still use Thunderbird as my personal e-mail client of choice. While it does have its own set of problems, it’s still one of the best remaining desktop e-email applications in terms of flexibility, security and user experience. It is also free and Open Source and enjoys a huge community.

Thunderbird 52.x with my userChrome modifications
Thunderbird 52.x with my userChrome modifications
Thunderbird 52.x with my userChrome modifications

Since I’m quite picky when it comes to UI design, I’ve made a few changes that improve the look of Thunderbird. Nothing spectacular, just a couple of minor changes:

  • alternating colors for the folder- and message tree control

  • rectangular tabs, less padding, less waste of space

  • minor changes to the message preview- and header area.

  • includes some minor styling changes for the Thunderbird-Conversations add-on.

Here is the code (embedded gist, if that does not show up for some reason, the public gist is available on GitHub.

To install

  • find your TB profile directory.

  • If it does not already exist, create a new directory in your profile and name it chrome (all lower case).

  • Copy the userChrome.css that you’ll find inside the .ZIP you downloaded from GitHub into that freshly created directory. Under Linux, the case matters, the C must be capital, the extension lower case. The folder chrome must be all lowercase.

To activate it, you have to restart Thunderbird. If anything goes wrong and TB looks strange, you can simply remove that file from its folder. It does not change anything outside itself. No special settings are required and the modification is only tested on Thunderbird 52 or newer under Windows.