bug#65217: 29.1; set-frame-size gets confused and drops calls

[martin rudalics]

> I tried a small variant of this
>
> (let ((i 100))
>    (while (> i 0)
>      (scroll-bar-mode -1)
>      (sit-for 0.1)
>      (scroll-bar-mode 1)
>      (sit-for 0.1)
>      (setq i (1- i))))
>
> and it works, for both the GTK and Lucid toolkits.  The scroll bar is 
displayed and hidden repeatedly.

The scroll bar is displayed and hidden repeatedly in either case- The
surprising thing is that with GTK3 the frame shrinks continuously.

> In any case, there will always be pathological cases in which the
> window manager (who has the last word) does not do what the Elisp code
> requested.

It's not the window manager, its's the toolkit which has the first word
here.  GTK2, Motif or Lucid builds have no problems.

> But ISTM that telling Elisp programmers that such requests
> are "committed" asynchronously, and that they can "commit" them
> immediately by calling (redisplay t), should solve most similar
> problems.

People changing the tab bar or the default font may be hardly aware of
the fact that the toolkit stochastically resizes their frames behind
their backs.

martin