Yes, and the lack of a viable vertical tabs solution for Chrome (though some Chrome based browsers have native implementations).
I am baffled how anyone could still be using horizontal tabs as it is clearly inferior. I am also annoyed as hell that it is not native in Firefox.
Enabling the desired behavior likely requires quite a few steps beyond just installing the extension.
https://github.com/piroor/treestyletab/wiki/Code-snippets-fo...
Originally, Firefox had a dropdown menu that allowed the user to choose whether tabs were on the top, bottom, left, or right.
This has been an annoying trend with Firefox for some time. They take the default, expected functionality, marginalize it while saying "Users who prefer the old way can enable it in a setting / extension" and then the setting gets deprecated or the extension stops working.
See also: "Classic Theme Restorer".
All the while software that might work better as an extension is bundled with Firefox and enabled by default. e.g. "Pocket", "Hello".
I don't tend to work with a browser full-screen on my larger monitor (2560×1440) instead often using half the screen (so 1280px wide) or there abouts. My other screen is 1080×1920 (standard 1080 but portrait not landscape). In those cases I have less room for tabs on the side. It might be less of an issue but most of the side-tab options I tried had a minimum width noticeably wider than the minimum width of a tab in the standard layout.
What might work for me is tabs that can be flipped from horizontal to vertical at a keystroke, or perhaps even if they reacted to window size (with the default choice being easily overridden).
Mozilla sucks, but it is because all of this should be baked in, not because of pocket or whatever political thing that HN regularly brings up.
I have tried the vertical tab implementation in several other browsers and they are all inferior. Safari’s is hilariously bad.