*Solved* My bad, need to make sure that macOS is selected when choosing custom device size.
Using native.requestExit() for a macOS shows an error is not supported on device “iMac”. and does not close the app.
Documents indicate that native.requestExit() is what is used to close the app on macOS.
(Using Build: 2017.3068, running on macOS 10.11.6)
Any suggestions?