Install libgarcon-gtk3-1-0 by entering the following commands in the terminal:
sudo apt update sudo apt install libgarcon-gtk3-1-0
Description:
menu library for Xfce (GTK3 library)
garcon is a menu implementation that is compliant with the Desktop Menu Specification of freedesktop.org . This package contains the GTK-3 support library.
Homepage: http://www.xfce.org/
Version: 0.6.1-2
Section: universe/libs