Created attachment 119937 [details] Broken FIrefox CSD Global menu applet breaks Firefox CSD STEPS TO REPRODUCE 1. Add global menu applet to plasma panel 2. Configure Firefox to hide the title bar OBSERVED RESULT Window control buttons appear not in the same row as tabs EXPECTED RESULT Window control buttons appear in the same row as tabs SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE Neon (available in About System) KDE Plasma Version: 5.15.5 KDE Frameworks Version: 5.57.0 Qt Version: 5.12.0 ADDITIONAL INFORMATION
Is that a CSD title bar in that screenshot? (if you're unusre, attach output of xprop and clicking on firefox)
Created attachment 119949 [details] Firefox xprop log
I'm not sure. Please, look into attached xprop Firefox log file.
New information was added; changing status for inspection.
Firefox is choosing to draw its title like that. There's nothing we can do. Sorry