Tab look regression in versions 126.* and above (after 125.0.3)

[Monsterovich]

Describe the bug

This is version 128.0.
Firefox-UI-Fix version: latest

Expected behavior

That's how it looked in 125.0.3
Firefox-UI-Fix version: v8.5.1 (I think)

Screenshots

Above.

The blue border on the tabs on the sides is now gone, and there's also no border at the bottom of the tabs, which there should be, because the gray border between tabs still works.

OS

Linux

OS - Others

No response

Firefox Version

128.0

Distribution

• Original Lepton
• Lepton's photon style
• Lepton's proton style

Theme

• Light
• Dark
• Alpenglow (System: Light)
• Alpenglow (System: Dark)
• System Default
• Others: (e.g. Photon Colors, Google Chrome Dark, Fairytale Of Nature)

Theme - More Info

Marwaita (old version)

user.js setup

Let me just upload the whole chrome dir. This is the working version which I used in 125.0.3.

chrome.zip

user.js.zip

Additional context

No response

[Monsterovich]

I tried to correct the visual appearance through the options in about:config, but I couldn't find the right ones.

[Aleksandra0056]

I'm not using the Photon style, but I honestly think, that you found an important bug.

The outlines should indeed be shown on the borders of tabs and panels. I think, that other people should also tell if they experience this issue. I can test it on a virtual machine to confirm it, but it would take some minutes.

Here could be responses to why this issue happens, but I don't understand these developer notes since I'm not a developer:
https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/126
https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/127

[Monsterovich]

@Aleksandra0056

I'm not using the Photon style, but I honestly think, that you found an important bug.

Yeah, I first upgraded Firefox on my computer with KDE Plasma 6 and noticed this problem but thought it was an intentional change, then I saw the same thing on my PC with xfce4.

[Monsterovich]

I think it has something to do with the userChrome.tab.static_separator.selected_accent option, only the color was lighter then.

back then: