[subsection1h]

> Firefox also has vertical tabs via Sidebery and TreeStyleTab [...] but the look and feel honestly sucks

I wrote a custom stylesheet for Tree Style Tab years ago. Did you do this, and if so, what did you find lacking afterwards?

[jwells89]

With Firefox on macOS and to a lesser extent Windows there’s some jank at play, for example when hiding/showing the sidebar you sometimes see a white flash as it redraws. It feels a bit duct taped together.