Very nice looking UI! Powered by forked GTK+ 2 [1]. (First release almost 24 years ago [2]).
[1] https://github.com/Ardour/ardour/tree/9.0/libs/tk/ytk
[2] https://mail.gnome.org/archives/gtk-list/2002-March/msg00136...
[1] https://github.com/Ardour/ardour/tree/9.0/libs/tk/ytk
[2] https://mail.gnome.org/archives/gtk-list/2002-March/msg00136...
Implemented like any custom GTK+ 2 widget?
https://www.kicad.org/blog/2025/06/KiCad-and-Wayland-Support...
We have user reports that XWayland causes error when running many plugins (primarily those written use JUCE); we also have reports that using XNest tends to be more successful.