bug#39143: 26.3; `widget-complete' in `customize-option'

[Drew Adams]

> > You get this error/message: "Not in an editable field".
> > 1. That message is incorrect.  The cursor is definitely in an
> > editable field.
> 
> In Emacs 27 get the message "No completions available for this field"
> instead.  So this problem is already solved.

Good.  Thanks for the quick reply.

> > 2. Emacs should provide reasonable completion for both fields,
> > `Parameter' and `Value', for `default-frame-alist'.
> 
> It does provide completions for Parameter, although it's debatable
> whether they are "reasonable".

I guess you mean in Emacs 27.  (Not in Emacs 26, AFAICT.)

Trying an Emacs 27 snapshot from 2019-12-28, it seems
that the completion is reasonable enough.

So this report can be classified as an enhancement request
that we provide some (lax) completion for `Value'.  Thx.