Thunderbird/Firefox fonts

[Beerislife]

I've changed the default font and menu font from Noto to Inter but Thunderbird and Firefox are not using the menu font, even after closing and restarting the apps. I've checked the GTK-3 settings.ini and it is correct:

[Settings]
gtk-application-prefer-dark-theme=true
gtk-button-images=true
gtk-cursor-theme-name=Breeze-Red (left)
gtk-cursor-theme-size=24
gtk-decoration-layout=:minimize,maximize,close
gtk-enable-animations=true
gtk-font-name=Inter, 8
gtk-icon-theme-name=Papirus-Dark
gtk-menu-images=true
gtk-modules=colorreload-gtk-module:window-decorations-gtk-module
gtk-primary-button-warps-slider=false
gtk-theme-name=Breeze
gtk-toolbar-style=0
gtk-xft-dpi=98304​

Can anyone shed some light on this?

[Snowhog]

Clear caches?

[jlittle]

I find GTK settings files mystifying. There are many, strewn through .themes and .config, and the GTK project regularly breaks theming. I don't know about Thunderbird but Firefox in the past did its own thing with GTK somewhat.

I use the 10 point "Serif" font. .config/gtk-3.0/settings.ini says Serif, 10 and it works, but I didn't put that there.

What may have worked for me has been to use the KDE system settings, appearance, application style, "Configure GNOME/GTK Application Style..." button, "Get New GNOME/GTK Application Styles..." and downloaded a Numix black theme. The KDE downloads in various system settings screens are often buggy, and have been for a long time, but sometimes they have worked for me.

[Beerislife]

I use the Arc (dark) theme from the Papirus PPA and just installed the Gnome arc-theme but it hasn't changed anything.

I'll just hide the menu bars....