Install xnest by entering the following commands in the terminal:
sudo apt update sudo apt install xnest
Description:
Nested X server
Xnest is a nested X server that simply relays all its requests to another X server, where it runs as a client. This means that it appears as another window in your current X session. Xnest relies upon its parent X server for font services. . Use of the Xephyr X server instead of Xnest is recommended. . More information about X.Org can be found at:
Homepage: https://www.x.org/
Version: 2:1.19.6-1ubuntu4
Section: universe/x11