This one's been bugging me for a while. On macOS, Emacs automatically focuses (raises) other frames when one is closed.
This has the unfortunate side-effect that I could be moved from one macOS desktop/space to another when closing an Emacs frame.
Finally managed do something about it. Since I install Emacs on macOS via homebrew, a small patch on emacs-plus recipe small patch on emacs-plus recipe did the job.
UPDATE: Pull request merged in d12frosted/emacs-plus.
The patch patch has been merged into d12frosted/homebrew-emacs-plus. To use:
brew tap d12frosted/emacs-plus
brew install emacs-plus --without-spacemacs-icon --with-no-frame-refocus
Balance restored.