web extension issue on selecting tabs

What happened?

Hello, I'm using Waterfox v6.0.17 on Win10 and I have installed extension "Select After Closing Current 5.3" that you find here: https://addons.mozilla.org/en-US/firefox/addon/select-after-closing-current/

The extension was working correctly in the past, but in the last months it stopped working as expected.

This is my configuration for extension:

When I close a tab I expect that it is selected the last used tab, usually the tab on the left of the closed tab. But instead it selects the right tab, and then immediately after that it selects the last used tab (on the left).

I don't want this: it must select the tab on the left, keeping unloaded the tab on the right.

It's working correctly on firefox 128, but not on Waterfox. I'm not totally sure but I belive it stopped working in Waterfox aftedr you added vertical tabs.

Reproducible?

[X] I have checked that this issue cannot be reproduced on Mozilla Firefox.

Version

What platform are you seeing the problem on?

Windows

Relevant log output

No response

BrowserWorks / Waterfox