I solved adding the next code in userChrome.css, instead of using userContent.css, or maybe is neccessary to use both codes in each file:

:root:is([privatebrowsingmode="temporary"]) {
  --tabpanel-background-color: transparent !important;
}

Thanks, the " is wrong, in my case I use 'drop-indicator' and works fine. 💙

First try and seem doesn’t work.

I will try it without my theme soon. Seems like doesn’t work, maybe is a change in Firefox beta, I test the code always in there to update my theme for the next version.

ooh, thanks for the information, your knowledge is epic. 🤝

Seems like it solved now, thanks for all your help. 🤝

I hope they fix that, but seems like they don’t want, thanks for your help. 💙

hi, I notice the issue happens when the #sidebar-main is ‘expanded’, when collapsed the problem doesn’t appear, I removed the code gap: 0px !important; and that solve the issue, but that space between the buttons makes me nervous jeje I tried delete too that ‘overflow’ button to remove the ‘flickering’ but the problem persist.

I’m personally adding that code for a smooth transition, so I don’t want to remove it.

I forgot to mention that I’m testing the code in Developer-edition new changes arrived there. I will check if other of my code, with the code posted here, makes the issue happens.

.tab-group-label {
        #tabbrowser-tabs[orient="vertical"][expanded] & {
            width: 100% !important;
            text-align: start !important;
        }
    }

Seems like other code combined with this are incompatible (with a tab with sound) in my particular case, first I have to figure it out what of my other code is in conflict, rare all this situation. With your latest code, the issue persist.

decrease the maximum width

Exactly, the default is so large, like a sausage.

I don’t know why that happens, but the problem persists, I delete that code block and the problem disappear. I’m in Windows 10 with Firefox-developer-edition 141.0b3, maybe other code is doing that? Or in combination with another thing, how to know. Here is a video with the issue: https://imgur.com/a/2ZLIYVp

Wow, I don’t know how it works but works, I will research ‘CSS container’, to learn. I appreciate your help. 💙

Excellent, thank you. 👍

I tested it and don’t work for me, I said I was in Developer-edition, maybe in release version is different. Here is a video with the issue, the sidebar doesn’t expand when it is on the right side: https://imgur.com/a/zqsWpqf

Thank you, I will add it immediately :)

Hi, for some reason when the sidebar-main is expanded there are 2 styles for ‘tools-and extensions’, when there are just a few icons they display in vertical, and when there are more than a few they display in horizontal, and I would like to have always the styles for ‘tools-and-extensions’ in horizontal when sidebar is expanded, even if there are just a few of icons. But I can’t apply code when they are in ‘vertical + sidebar expanded’ and don’t affect when the sidebar is collapsed.

I see, thanks for the answer. 🫱🏻‍🫲🏼

Thanks. 😄👍 💙