Assume there are only one space - Desktop
1. emacs -Q
2. M-x toggle-frame-fullscreen
   Now there are two spaces - Desktop and *scratch*
3. eval (make-frame `((parent-frame . ,(window-frame))))
   Now there are three spaces:
   - Desktop
   - Empty space named *scratch* with emacs menu
   - *scratch* with emacs frames but without menu

Although attached patch solves this problem for me these cases still not
handled right way:

1. Removing parent-frame property leaves the frame is same space:

(let ((new-frame (make-frame `((parent-frame . ,(window-frame))))))
  (modify-frame-parameters new-frame `((parent-frame . nil))))

Maybe child frame must go fullscreen if ex-parent frame is in
fullscreen.

2. Setting parent frame after frame creation:

(let ((frame (window-frame))
      (new-frame (make-frame)))
  (modify-frame-parameters new-frame `((parent-frame . ,frame))))

Thanks!

In GNU Emacs 27.0.50 (build 1, x86_64-apple-darwin18.6.0, NS
appkit-1671.50 Version 10.14.5 (Build 18F132))
Windowing system distributor 'Apple', version 10.3.1671
System Description:  Mac OS X 10.14.5