Thunderbird color by categories (working on v115.6.1)

TbColorCategories.md

Thunderbird color by categories

• Navigate to Help > Troubleshooting Information > Profile Directory > Open Directory
• Close Thunderbird
• Create a folder named chrome (all lowercase)
• Create a file named userChrome.css
• Insert

/* Calendar  - set event category colour instead of calendar colour */
 .calendar-category-box {
    width: 100% !important;
    height: 100% !important;
    margin: 0 0;
    padding: 0 0;
     }

• Save the File
• Open Thunderbird
• Go to Settings > General > Config Editor
• Set toolkit.legacyUserProfileCustomizations.stylesheets to true
• Restart Thunderbird
• Done!