Should customizing default-frame-alist change existing frames?

[Per Abrahamsen]

RMS asked me to look at this, but did not say what to do.

I can see two solutions:

1. Change the doc string to say that existing frames will not be
   affected by setting default-frame-alist, only new ones. 

2. Add a :set method that applies the frame parameters to all existing
   frames.

I think #2 could be dangerous, especially if there are any "special
purpose" (like ediff of speedbar) frames around.  

One could try to be smart about it, by only changing the current
frame, or only changing the frame is there is only one, or only
changing the frames which were not marked as "special", or whose frame
parameters were close to the old value.  However, such partial
appliances might be even more confusing.

What do you think?

> --- Begin Message ---
>
>
>
> Subject: 
>
> emacs customize / frame color setting [almost] bug
>
>
>
>
> Date: 
>
> Thu, 28 Feb 2002 10:53:51 -0600
>
>
>
>
> Hello,
>
> (I would use send-pr, except the company firewall won't let my GNU machine
> [Linux] roam free.  Down with corrals!  I'll work on reconfiguring the
> sendmail.cf so I can get through properly.:-)
>
> Problem:
>
> This is really a problem with user expectation, but it is surprising enough
> that something should be done ...
>
> The default frame colors are getting set from within the customize buffer,
> but the changes are not immediately visible (since the "defaults" are
> applied when a new frame initializes).
>
> Steps to repeat:
>
> - M-x customize-apropos <enter>
> - default-frame-alist <enter>
> - Insert (or change) the background color to something different (such as
> gray20, etc)
> - Click "Save for Current Session"
>
> The result is that the color does not change as I expected it would.  I have
> to start up a new frame so the default colors take effect.
>
> Perhaps the correct response is "Yup, that's how it is", but it leaves users
> [such as me] confused [at least for a while].
>
> The version of emacs is:
> GNU Emacs 21.2.50.1 (i686-linux-gnu, X toolkit, Xaw3d scroll bars) of
> 2002-01-16 on rmauctor.lsil.com
>
> Thanks!
>
> --- End Message ---