Actually, I didn't remember it right, it wasn't tkinter. It was probably some other popular GUI library. I just tested tkinter + threading/multiprocessing on Py

Actually, I didn't remember it right, it wasn't tkinter. It was probably some other popular GUI library. I just tested tkinter + threading/multiprocessing on Python 3.4.3 on Windows 7, and it works fine. I'm sorry for the false information.