Install gtk2-engines-sugar by entering the following commands in the terminal:
sudo apt update sudo apt install gtk2-engines-sugar
Description:
Sugar Learning Platform - GTK+ 2.x theme engine
Sugar Learning Platform promotes collaborative learning through Sugar Activities that encourage critical thinking, the heart of a quality education. Designed from the ground up especially for children, Sugar offers an alternative to traditional “office-desktop” software. . This package contains the GTK+ theme engine for Sugar.
Homepage: http://wiki.sugarlabs.org/go/Sugar
Version: 0.112-1
Section: universe/oldlibs