Multi-Account Containers extension - tab colours inheriting from sites

Recently, on certain sites, Firefox Multi-Account Containers extension has been ignoring my assigned tab colours, and picking them up from the site open within the tab. I can’t share URL’s to demonstrate this as they are dev sites only available locally right now.

I assume this is a bug? Is there a particular style declaration that might be overriding the style for the tab? It messes things up for me because I can’t tell at a glance whether a tab is admin/front end etc.

How would it pick up the color from the site inside the container? Or what color would it pick?

I know it sounds unlikely - but I came to this conclusion based on observing the two things change at more or less the same time, to what appears to be the same value (black). I don’t have any black tabs configured.

I’ll keep digging around. Something is making the tab ignore its colour setting.

I guess what I was asking is “what is the site’s color”.

Also, there is no mechanism for a site to tell the browser what container it wants to be in.

Maybe do you mean that it won’t prompt to change a container when following a link?

Many colours. But the one that had changed recently was #292929. The tab is also now black (although I can’t tell the exact hex code).

There is a css declaration targetting the html node of

color: #292929;

which caught my eye.

Nothing to do with following links. I also wasn’t thinking that the site was choosing the container - I open hosts in different colour containers based on their role (e.g admin, front end etc.)