bug#38146: 26.1; set-frame-width sometimes does not work on OSX

[martin rudalics <rudalics@gmx.at>]

 > When I do:
 >
 >      $ emacs -Q -l frame.el
 >
 > where frame.el consists of the forms:
 >
 >      (defface item-frame
 >        '((((class color))
 >           (:family "DejaVu Sans Mono"
 >            :height 151)))
 >        "Face for frame to demonstrate the issue.")
 >
 >      (progn
 >        (set-frame-font (face-font 'item-frame))
 >        (set-frame-width nil 102)
 >        (set-frame-position nil
 >                            (/ (- (display-pixel-width) (frame-pixel-width)) 2)
 >                            (cdr (frame-position))))
 >
 > and then, in the resulting Emacs instance, do:
 >
 >      M-: (frame-width) RET
 >
 > I get: 80.
 >
 > However, the expected result is 102, because the form
 > (set-frame-width nil 102) above sets the frame width to 102.
 >
 > I get the expected value of 102 if I remove the call to
 > set-frame-position. This is unexpected, because whether
 > set-frame-position is called should not influence the frame width.
 >
 > When I evaluate the form (set-frame-width nil 102) in the resulting
 > Emacs instance, the frame width is set to 102 as expected.

Here I get 102, for example with a GNUstep build on Debian.  The
behavior you see is OS and window manager dependent.  Sometimes
setting all desired values in one 'modify-frame-parameters' call
helps.

martin