Install xdg-desktop-portal-gtk by entering the following commands in the terminal:
sudo apt update sudo apt install xdg-desktop-portal-gtk
Description:
GTK+/GNOME portal backend for xdg-desktop-portal
xdg-desktop-portal-gtk provides a GTK+/GNOME implementation for the desktop-agnostic xdg-desktop-portal service. This allows sandboxed applications to request services from outside the sandbox using GTK+ GUIs (app chooser, file chooser, print dialog) or using GNOME services (session manager, screenshot provider).
Homepage: http://flatpak.org/
Version: 0.11-1
Section: universe/gnome