Explanation of need for Multi Threading GUI programming

Question

I\'m looking for a good explanation of the need to use multi-threading in graphical applications. In the examples below Python is used but the question is not python specific it

Answer 1

Your understanding is correct. If an application isn't muli-threaded the application waits for every operation to finish. When your application is multi-threaded you use one thread to handle GUI actions and another to process the files.

I don't have an article or a reference to something similar. Maybe it helps if you think of threads as people, each has it's own job and each can only do one thing at a time.