@npetri, Admin config field pages_list_display_field is a mystery to me…
It is referenced in a macro in Admin template /user/plugins/admin/themes/grav/templates/pages.html.twig but it looks like that template is never being called, or at least the macro in that template.
Maybe the page list is being generated in js, but I haven’t found a reference to pages_list_display_field in js.