Themes and vertical tabs
Firefox Color themes and vertical tabs—it’s enough to drive you crazy. For starters, most existing themes don’t support vertical tabs, so the tab bar just looks awful. And even after I went to the trouble of creating my own theme, a subsequent update left the sidebar without the actual background image—it’s just a plain, solid color now. What’s the point of putting in all that effort to make things look good, only for a single Firefox update to ruin everything? They’re pushing these vertical tabs on us, yet they haven’t even bothered to implement proper support for them. I really wish they’d finally address the vertical tabs and give them a decent, polished look; it’s not a bad feature, it’s just half-baked.
All Replies (2)
There was a pushback to backgrounds expanding without authors control into this area so this is the result. 🤷
There's now a new opt–in way to fill the vertical tabs, otherwise these will just use the older "toolbar" way of styling, I think it was recently published in https://blog.mozilla.org/addons/2026/09/29/nova-is-here-what-changes-for-your-firefox-theme/
I’ve figured out exactly where the problem lies: if the side panel is collapsed and only expands when you hover the cursor over it, the background appears as a solid color; however, if it remains fully expanded or fully collapsed at all times, the background displays as a wallpaper. This affects all themes, not just the ones I created. Interestingly, it was working perfectly fine just yesterday, but since the update, it’s no longer functioning as it should. Furthermore, I installed a different version of Firefox—I’m currently on 159, so I installed 158 (though I’m not entirely sure if that was the exact version I had before)—and it doesn’t work correctly in that older version either. I suppose we’ll just have to wait for a patch to fix it.
You must log in to your account to reply to posts. Please start a new question, if you do not have an account yet.