Super simple, works, no problems yet

Space-efficient vertical tabs with marker tabs to organize groups of tabs

Nice and low footprint addon that manages the tabs in the most Effective way possible. It makes itself a sidebar which complement firefox well, and feel very intuitive to use.

1. Не сокращаются заголовки закреплённых вкладок до размера одного значка
2. Настройка внешнего вида очень трудоёмкая

Very simple and easy to customize for people who close to CSS

Support site down, so have to leave a request here: If a site has no icon, the title should still be lined up with the other titles, i.e. there should be an empty space of the same size as an icon. Please line up by default or suggest a custom CSS for that.

is it possible to add per-tab persistence configuration? that would be very useful esp. on pdfjs tabs (which is local, and might be restricted therefore)

Perfect, thanks

Amazingly useful and innovative.

We can create "marker tabs" at will, but we can rename one only when we create it, as follows:

(right click anywhere on the left side list of tabs)
> new marker tab
> (in the address bar, replace "MarkerNameHere" with the name of your choice. It also accepts spaces.)
> (type the ENTER key)

This addon is also open source and does not require any dangerous permissions.
I was using "tree style tab" before, but the multiple level of folding were very annoying to me.
Thanks a lot :)

Great combination of tab grouping and tab menu. Simple, helpful, and unobtrusive. Two things would make it really great: dim unloaded tabs and tab search or filtering. But I still give it 5 stars because I love the easiness and clever simplicity.

Good addon. A bit too simplistic, but at least it doesn't crash the browser, like others do.

I like the simplicity.

I couldn't guess whether overtyping 'MarkerNameHere' would (a) rename the marker; or (b) result in an invalid URL.

Also, re: https://framagit.org/ariasuni/tabcenter-reborn/issues/66 Tab Sidebar is is one of four (or more) extensions that use the same word, 'Tabs', in the sidebar.

Please, can you use a more distinctive phrase?

Thanks