Install libreoffice-gtk3 by entering the following commands in the terminal:
sudo apt update sudo apt install libreoffice-gtk3
Description:
office productivity suite -- GTK+ 3 integration
LibreOffice is a full-featured office productivity suite that provides a near drop-in replacement for Microsoft(R) Office. . This package contains the Gtk plugin for drawing LibreOffices widgets with Gtk+ 3 and Gtk/GNOMEish print dialog when running under GNOME.
Homepage: http://www.libreoffice.org
Version: 1:6.0.3-0ubuntu1
Section: gnome