Close_windows_when_empty not working on Mac

[rubs]

"close_windows_when_empty": true is not working on Mac. I open a file, press cmd+W, the tab closes but the Sublime window remains open.
Using Sublime 4 build 4121. Mac OS 10.14.6.

[bschaaf]

See https://github.com/sublimehq/sublime_text/issues/4998