Just had another look. So, my original statement that other gtk-3 apps show "Recent" for Save is probably wrong (also checked eog and evince). Not sure what made me believe that. Only gtk-2 apps do (e.g. gimp, inkscape, chromium, libreoffice, all checked under Ubuntu 16.04).
Nevertheless, it's an inconsistency of the user experience.
Just had another look. So, my original statement that other gtk-3 apps show "Recent" for Save is probably wrong (also checked eog and evince). Not sure what made me believe that. Only gtk-2 apps do (e.g. gimp, inkscape, chromium, libreoffice, all checked under Ubuntu 16.04).
Nevertheless, it's an inconsistency of the user experience.