Re: "CHANGED outside Customize" in frames customization group

[martin rudalics]

>     IIUC `custom-reevaluate-setting' can be used to set a variable after
>     some environment value has been established as for `blink-cursor-mode'.
>     The situation seems completely different for `default-frame-alist'.
>
> In what way is it different?

`frame-notice-user-settings' may set the value of `default-frame-alist'
overriding a saved or standard value.  The value of `blink-cursor-mode'
is not reset by Emacs.

>       The first reason is immediately visible
>     when starting Emacs without your .emacs.  The value is here:
>
>     ((left-fringe) (right-fringe) (menu-bar-lines . 1) (tool-bar-lines . 1))
>
>     I know how to get rid of the -fringe entries.
>
> ISTR someone recently posted a patch that would affect the handling
> of fringes in `default-frame-alist'.  Would they get rid of those?

I hope so.

>                                               But I don't know what to
>     do with the -line entries (which are BTW already there in Emacs 21).
>
> Why does anything need to be done with them?
> Could you just leave them alone?
> Or else change the numbers?
>
>     Delete them in the customization buffer, save your settings, restart
>     Emacs, and here they are again.
>
> That is arguably a bug, and maybe we should fix it.
> However, I do not see that this bug is so grave
> that we should conclude that `default-frame-alist' is
> unsuitable for use with Custom.

The bug causes the "CHANGED outside Customize ..." state.

>     A second reason is the function `modify-all-frames-parameters'.  This
>     function may set `default-frame-alist'.  Customize `tool-bar-mode' or
>     `fringe-mode' and you will change your `default-frame-alist' settings.
>
> I don't see a problem in that.  Why do you think it is a problem?
> What aspect of it is the problem?

Customizing `fringe-mode' calls `modify-all-frames-parameters' which
sets `default-frame-alist'.  I'm now told that `default-frame-alist' was
CHANGED outside Customize although all I actually did was _customizing_
some option.

> If the problem is in some detail of the behavior of Custom when it is
> used on `default-frame-alist', maybe we can fix that detail.
> For instance, maybe those other commands should do somethingto inform
> Custom of the changes, so that it looks like `default-frame-alist'
> was set using Custom.

Suppose I set and save a new value for `fringe-mode'.  Should Emacs
automatically set and save the new value for `default-frame-alist'?