Seems to work in zen browser which is firefox based. I make a whole bunch of tabs, randomly re-arrange them and when I start closing them at random it's always going to the left.

Works. With vertical tabs it focus the tab above.

Tut was es tun soll. OHNE unnötige Berechtigungen zu verlagen. Extrem gut.

Yes

Works good, except that I have to uninstall and reinstall each time I start/restart firefox.

Make firefox OBEY customers again.

The extension doesn't work at all for me. Running on Firefox 122.0.1 (64 bit version).

just started using it , works fine need more of these hard to find.

Works for me with Firefox, 89.0.2 (July, 2021)

Sometimes works but sometimes focus is on right

Thanks!

Works great and does exactly what it says it does.

Really natural and smooth tab transitions, no other addon can be like this.

doesn't work after wake up from hibernate

Now is OK.

Doesn't work with LTS

It does not work... it worked once but no more.

Does not work for me either. Correction... it worked once, then no longer.
This is a shame as it's something that should be built into Firefox.

Doesn't work reliably. When works, results in noticeable flickering(*).
(*) I suspect that it's because it allows "default" tab selection to be done first.

"Select After Closing Current" seems to be a better choice: works reliably so far and flickering is less(*)
(*) though it also seems to be not able to completely prevent default tab selection