Re: "Attempt to modify read-only object" error with set-frame-configuration

[martin rudalics]

>>BTW it should be _much_ simpler to analyze the
>>`horizontal-scroll-bars' problem first.
>
>
> Why do you think it's much simpler?

I guess because it has one clearly identifiable place where it gets set.
`frame-initialize' has

              (or (assq 'horizontal-scroll-bars frame-initial-frame-alist)
                  (setq frame-initial-frame-alist
                        (cons '(horizontal-scroll-bars . t)
                              frame-initial-frame-alist)))

and I don't have the slightest idea where and how visibility is set.