Created attachment 155307 [details] Epiphany with the Breeze theme, with no scrollbar visible SUMMARY In apps using WebKitGtk the scrollbar is invisible, and having the cursor at the right edge does not make it appear. With the Adwaita theme there is a thin version of the scrollbar, which when moused over expands to the full size scrollbar that can be dragged around and such. The easiest app to use to reproduce this with is probably GNOME Web/Epiphany. STEPS TO REPRODUCE 1. Open GNOME Web 2. Open a website that can be scrolled 3. Try to find the scrollbar OBSERVED RESULT No scrollbar is visible at all. EXPECTED RESULT There should be a thin scrollbar, which expands when moused over. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.26.5 KDE Frameworks Version: 5.101.0 Qt Version: 5.15.8 GNOME Web Version: 43.0 GTK Version: 3.24.36 Kernel Version: 6.1.4-arch1-1 (64-bit) Graphics Platform: Wayland ADDITIONAL INFORMATION I noticed in most other GTK apps with the Breeze theme the scrollbar is also invisible, but hovering anywhere over the scrollable widget makes the scrollbar appear, so the theme works fine in those cases but not in WebKitGtk.
Created attachment 155308 [details] Epiphany with the Adwaita-dark theme, with the scrollbar visible on the right
Created attachment 155422 [details] Epiphany with the Breeze theme and overlay scrolling disabled Something else I just noticed is that with overlay scrolling disabled (by setting `gtk-overlay-scrolling=false` in `~/.config/gtk-3.0/settings.ini` and/or running `gsettings set org.gnome.desktop.interface overlay-scrolling false` in a terminal) the scrollbar in WebKitGtk looks broken, specifically while the background is present the slider itself is invisible. Fortunately, the scrollbar is actually still usable, dragging on where the scrollbar should be still scrolls the window as normal (that also works with overlay scrolling enabled). Also, the reason I think it's WebKitGtk and not just Epiphany/GNOME Web is that I first ran into this issue when experimenting with the [Tauri](https://tauri.app/) framework, which on Linux uses WebKitGtk, so any app that uses Tauri on Linux would also cause this issue to appear if the Breeze GTK theme is used.
Evolution has similar scrollbar behaviour (i.e., invisible/missing in the message view pane) under the Breeze theme, so I suspect it is also affected by this bug.
This should be fixed by https://invent.kde.org/plasma/breeze-gtk/-/merge_requests/93 I’d appreciate if you could try again, then I will backport this to stable Plasma.
I see the commits in the merge request are present in Plasma 6.2.0 and newer already, and indeed with Plasma 6.2.2 on Arch Linux Epiphany/GNOME Web 47.2 (with the GTK_THEME=Breeze environment variable set for testing since it uses libadwaita now) has working scrollbars, and so does the Tauri app I was using, thanks!
Oh, right, this was already merged before my vacation, so it’s already in 6.2 ;) cool, thanks for letting me know!