> This said, I have the impression that this is already done (at least partly)
> in newer Emacsen.
Don't know what it's worth.
In GNU Emacs 25.2.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.22.10)
of 2017-04-22 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.11903000
System Description: Arch Linux
bug#27422: 25.2; Desktop mode fails to restore window registers
>> This said, I have the impression that this is already done (at least partly)
>> in newer Emacsen.
> Don't know what it's worth.
I think he means that C-x r f should work as intended. To fix C-x r w
accordingly you would have to write a new function, say
‘window-state-to-register’, based on ‘window-state-get’ and, when you
later jump to that register, use ‘window-state-put’ to put the state
saved in that register into the selected window. Binding C-x r w to
that new function should then produce a register you can restore in a
later session. Could you try implementing and testing that?