SUMMARY Newly added toolbar cannot be removed. I can remove all the buttons (from 3 different default toolbars which show at random times and have generic conflicting names... like "session toolbar" and "main toolbar<session>") but a thin empty toolbar will still show on the screen. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.21.4 KDE Frameworks Version: 5.81.0 Qt Version: 5.15.2 Kernel Version: 5.11.16-arch1-1 OS Type: 64-bit Graphics Platform: X11 ADDITIONAL INFORMATION Feature was repeatedly voted against e.g. https://forum.kde.org/viewtopic.php?t=97684 (PS i like this one because the pro argument is that it is "as useful as a menu bar"... which does have an option to hide it)
Cannot reproduce FWIW
on arch package 21.04.1 I can now hide them via "Settings > Toolbar shown > clear all options" and they indeed go away without any vestige.