Containers are not usually associated with GUI applications, but there may be times when one might still want to run such a program inside a container, for example to isolate the application's dependencies. Installing a GUI application in a container means that not only the application, but also all its specific dependencies are encapsulated inside the container (respectively, the container image), and can therefore reliably be removed from the system in a single step.
The primary challenge is to let a container communicate with the host's display system, so that it can create GUI windows on the host. A GUI application will likely also need to share files with the host system, which in turn requires the appropriate user permissions.
In this example, I will use the pinta paint program, which requires the Mono runtime. I do not use any other programs that depend on Mono, and as I like to keep my system installation re