bug#1322: dedicated *Help* and M-x help-for-help

[martin rudalics]

> I'm not sure this will be sufficient. Remember that help-for-help
> has entries that bring up info, NEWS, etc. Now if *Help*
> is the only thing in special-display-buffer-names and
> help-for-help is in it's own frame, accessing these help
> functions through help-for-help is going to spawn another frame.
>
> To see this:
>
>   emacs -Q
>   M-: (setq special-display-buffer-names '("*Help*"))
>   f1 f1 C-a
>   Return to first frame
>   f1 f1 C-n
>
> Now there's four frames open!

Yes.

> Surely this is not the intended
> behaviour of help-for-help, even after fixing the iconification
> issue.

It is.  `special-display-popup-frame', for whatever reason, has

  (set-window-dedicated-p (frame-selected-window frame) t)

so C-a and C-n are not allowed to use the help window because they do
not put their information into *Help*.

> One way to work around that is to restrict help-for-help to the
> original frame in some way. If that is not acceptable then
> shouldn't we at least make sure that the user's commands are
> taking effect in the correct frame? It doesn't seem right that a
> help command will display differently when you run it through
> help-for-help.

We'd have to write our own `special-display-function' for that.

martin