Someone in Chrome/Edge/Safari must be thinking about doing this, I don't know why it hasn't been cloned. Can't be too hard to do.
Which raises the question: why would FF sabotage it? Why isn't it easy to hide the default tabs, and why does the sidebar have the name of the extension providing it stuck at the top?
They had all of the warning in the world about how important this extension was to people years before finally removing XUL, half a decade later you still can only repair the display problems through CSS that isn't kept consistent from version to version, and feature requests/bug reports on the issue are filled with antagonism from the project.
> I don't know why it hasn't been cloned
opera had vertical, grouped tabs over twenty years ago.
Is it this one?
https://addons.mozilla.org/en-US/firefox/addon/tree-style-ta...
with TST whenever I need to reorder/re-group things, it's a pain (I still appreciate TST a lot)
No - it is figuratively the killer feature.
If it were literally the killer function this would be a very different discussion.
vs
> (literally the killer) feature
A "killer feature" is a phrase with its own meaning so we can treat it as an atom and apply modifiers to it. The order of operations matters, and I posit that the OP placed their imaginary parentheses as I did in my first example.
Easy, most people never use more than five or six tabs because it’s annoying to have more. TST is a solution to a marginal use case so no one invests the time into developing it.