bug#25851: 25.2; GTK warning when starting Emacs when desktop file has more than one frame

[martin rudalics]

> But no it is not obviously the double-buffering IIUC. I evaluated:
>
>    (modify-frame-parameters nil '((inhibit-double-buffering . t)))
>
> in each of the frames, but the flashing when switching between
> them was not effected.

Earlier you said that:

  [This was after I'd maximized the three frames so that I could use
  them, rather than when they were the smaller size at which they
  were specified in the desktop file I tested with. I tried
  restoring them down to their previous size and didn't see the
  flash, then maximised them again and the flashing was back. I
  suppose that the flashing might also be happening when they're
  small but that my eye isn't fast enough to detect it; not sure.]

Is the flashing reproducible with emacs -Q, two times C-x 5 2, <M-f10>
for each frame and then Alt-tabbing between the resulting frames?  Or do
you need additional customizations?

martin