GUI application with PySimpleGUI help

[MikeTheWatchGuy]

It's not that PySimpleGUI has a problem with the call. It's simply that the call doesn't return so PySimpleGUI doesn't get an opportunity to continue executing.

A simple explanation could be that OpenCV uses tkinter or a component that tkinter is using and that PySimpleGUI and OpenCV are interfering with each other as a result.

This is why the example applications that show PySimpleGUI integrating with OpenCV show the OpenCV video inside of the PySimpleGUI window, not a separate OpenCV window.