bug#25511: 26.0.50; modify-frame-parameters modifies undesignated parameter?

[Katsumi Yamaoka <yamaoka@jpl.org>]

On Tue, 24 Jan 2017 08:46:30 +0100, martin rudalics wrote:
> Does this imply that GTK cannot handle Windows' multiple monitors?  Can
> you invoke ‘display-monitor-attributes-list’ for both displays and on
> the native and the cygwin builds?

Windows native 25.1.90 shows:
(((geometry 0 0 1366 768)
  (workarea 0 0 1366 738)
  (mm-size 344 194)
  (name . "\\\\.\\DISPLAY1") ;; Note PC
  (frames))
 ((geometry -258 -1080 1920 1080)
  (workarea -258 -1080 1920 1050)
  (mm-size 531 299)
  (name . "\\\\.\\DISPLAY2") ;; External display
  (frames #<frame emacs@YAMAOKA-PC 04bbd448>)))

26.0.50 built on Cygwin shows:
(((geometry 258 1080 1366 768)
  (workarea 258 1080 1366 768)
  (mm-size 347 195)
  (frames)
  (source . "Gdk"))
 ((geometry 0 0 1920 1080)
  (workarea 0 0 1920 1080)
  (mm-size 488 274)
  (frames #<frame emacs@yamaoka-PC 0x77f446a8>)
  (source . "Gdk")))

The values except for `frames' don't vary whether a frame stays
at DISPLAY1 or DISPLAY2.

Thanks for the suggestions about ‘after-make-frame-functions’,
‘frame-inhibit-implied-resize’, and others.  I didn't recall
I've been using ‘after-make-frame-functions’ for the other
purposes. ;-)  I'll try them one by one from now on.  Anyway, I
concluded I should not use dirty codes such as advising the core
functions, as much as possible.

Regards,