I gave three stars in recognition of the great history and usefulness of this Great Extension
It is too bad the Dictators at Mozilla forced you to inhibit this extension to support their egocentric view of FireFox.
I have had to disable Colorful Tabs it on all systems as 57+ the colours are too irritating
and the extension does not work on <57 (no colours).
Possibly you should consider other browsers, currently I am testing Opera, which is OK (not great).
The advantage Opera has for me at the moment is support for Web Pages saved in a Single File Format
which the Mozilla Dictators killed.
Also, Make Use Of has identified some new players in the browser world,
hopefully one of them will emerge to fill the void Mozilla has created.
Good Luck (& Skill!) as you move forward,
and remember,
Great Technology Does Not Dictate, It Delivers with Options ~mm