Create a custom GUI in under five minutes.
Since you don't mention any crashes, sounds like your Read is returning normally and you're simply exiting the program. What may be happening is that you're using a Submit() or OK() button. By default those buttons have a parameter named bind_return_key set to true. If you're using a built-in button then try adding the parameter ... bind_return_key=False... to the call. Or you can switch to making your own buttons by using a call like Button("Submit"). Plain buttons like this don't have the enter key bound to them like the built-in ones do. If you have further problems, come log an issue on the github site (www.PySimpleGUI.com)
If you are on a Mac, you will not see any change. You will see this message printed out:
*** Changing look and feel is not supported on Mac platform ***'
Make sure you make the call to ChangeLookAndFeel PRIOR to your layout definition. The layout needs to know the colors.
You can also call SetOptions with the individual color choices that you want. It is not blocked from being called by Macs. The reason for blocking the Look and Feel call is that button colors do not work on a Mac.
Feel free to log an issue on the github if it continues.