This addon does what it says and is an improvement upon the dark Firefox default. Till recently I used ColorfulTabs even though these days (post quantum) it only colored the active tab, because it also made the background of the inactive tabs grey (not black). But ColorfulTabs has bugs. This app, Tab Colors, just does what it says: colours the active tab one colour (selectable) and the inactive tabs another colour (likewise selectable).

There is also the option to apply the above settings only when visiting one URL.

I thought that the latter setting was offering a way of changing the colour of the tab of one website. So I added a URL and this addon *seemed* to stop working. I am not sure why one would want to have colorful tabs only when visiting one URL. But I would like to be able to set the colours of the tabs of a few of my most important websites so that I could select them in a hurry.

It would also help if it were only the active tab itself, and perhaps the address bar, but not my link bar that were coloured since it makes the links a bit difficult to see.

But this is already better than the buggy ColorfulTabs so I recommend it, and made a tiny donation.