SUMMARY Open System Settings > Application Styles > Configure > GNOME/GTK Application Style .... Choose `Breeze` as the GTK3 theme. The preview is that of Breeze Dark and Firefox, a GTK3 application, uses Breeze Dark confirming the preview. STEPS TO REPRODUCE 1. Choose Breeze as the GTK3 theme in System Settings > Application Styles > Configure > GNOME/GTK Application Style ... OBSERVED RESULT 1. Open the preview. The preview is of Breeze-Dark and not of Breeze 2. Open Firefox. It uses Breeze-Dark, not Breeze EXPECTED RESULT Both the preview and applications should use Breeze and not Breeze-Dark SOFTWARE/OS VERSIONS Operating System: Kubuntu 20.04 KDE Plasma Version: 5.18.2 KDE Frameworks Version: 5.67.0 Qt Version: 5.12.5
The Breeze GTK theme gets recolored based on your color scheme so I assume you're using a dark color scheme?
Thank you for clarifying! I'll change the status to RESOLVED.