Most Blue Ocean changes to the Breeze QStyle have been implemented in the GTK widget theme, but tab widgets in GTK applications still have not had their appearance updated. See bug 443919.
STEPS TO REPRODUCE
1. gtk3-widget-factory with GTK_THEME=Breeze
Tab widgets are not styled to appear identical between Qt and GTK apps.
After a series of recent commits to implement the new Blue Ocean design, equivalent widgets should be styled identically across widget toolkits.
KDE Plasma Version: 5.24.1
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.2
Scrollbars, buttons, radio buttons, checkboxes, menus, and most other widgets appear to have completed the Blue Ocean transition. I have not noticed if there are any other lingering artefacts; it is possible that one or two other widgets slipped under the radar. As of now I am only aware of tabs not having their style updated.
Git commit 7b6cf965b6bd64c2e6d9077745eccf58ff981b8c by Nate Graham, on behalf of Artem Grinev.
Committed on 09/05/2022 at 21:23.
Pushed by ngraham into branch 'master'.
gtk3, gtk4: implement Blue Ocean tab styling
M +107 -35 src/gtk3/widgets/_notebook.scss
M +107 -35 src/gtk4/widgets/_notebook.scss