I really hate that ugly Adwaita fallback theme, I never selected this as my theme, and is not my default set theme, but for some reason this theme is overriding my set default theme for certain save prompts, such as my web browser.
For comparison’s sake, on the left Vivaldi shows Adwaita theme on the Save As window, and Firefox on the right shows my actual theme Arc Darker which is what it’s supposed to be.
One random update and all a sudden GNOME themes overriding my default set system theme, breaking consistency with the overall looks. I couldn’t find anywhere in my theme settings where it chooses Adwaita over my chosen theme which by the is a GTK2/GTK3 theme.
The ONLY Adwaita set theme is for the cursor, and that is all. Nowhere does it say using Adwaita for Desktop, Window Border, Icons or Controls. Unless there’s some hidden GNOME setting somewhere that’s overriding my defaults, which shouldn’t be a thing. This isn’t just limited to web browser btw, this is for other GNOME apps too.
Other apps that I use like gnome-calculator it use to be using my system desktop theme before, but now it’s just using Adwaita theme, and I don’t know why it changed on me like this.
Also that theme you linked to only changes the color scheme of the browser, not the app windows themselves, it still uses Adwaita theme on the window boxes for Save prompts.
Theming across toolkits - qt and gnome - is and has always been an issue.
It has gotten better over the years - but every now and then major changes e.g.gnome 3 → Gnome40 breaks theming.
There is not much to do other than adapt yourself and if you are using a custom theme adjust your theme accordingly - and if you are using a 3rd party theme and that theme is actively maintained - contact the developer.
That is due to recent changes in the Gnome theme engine.
Other apps that I use like gnome-calculator it use to be using my system desktop theme before, but now it’s just using Adwaita theme, and I don’t know why it changed on me like this.
Unless your theme is libadwaita/GTK4 compatible and the theme utility of your desktop support GTK4 themes (I think it’s not), you could maybe check if the applications use GTK3, I have no problems with galculator.
Also that theme you linked to only changes the color scheme of the browser, not the app windows themselves, it still uses Adwaita theme on the window boxes for Save prompts.
Because Vivaldi don’t support GTK themes, changing the color scheme is the best you can expect.
