Re: Question about customising faces

[Eli Zaretskii]

> From: Joost Kremers <joostkremers@fastmail.fm>
> Cc: help-gnu-emacs@gnu.org
> Date: Tue, 30 Aug 2022 08:44:53 +0200
> 
> > Please show a recipe, starting from "emacs -Q", to reproduce the issue.
> 
> I do the following, starting from `emacs -Q`:
> 
> - Evaluate the following `set-face-attribute` calls (with FRAME set to nil, no
>   use of `unspecified`):
> 
>   (set-face-attribute 'isearch nil :background nil :foreground "#d33682")
>   (set-face-attribute 'isearch-group-1 nil :background "lightskyblue1" 
> :foreground "#d33682")
>   (set-face-attribute 'isearch-group-2 nil :background "DarkSeaGreen1" 
> :foreground "#d33682")
>   (set-face-attribute 'lazy-highlight  nil :background nil :foreground nil 
> :box "#d33682")
> 
> - Start isearch in any buffer and observe the changed faces.
> 
> - Create a new frame with `C-x 5 2`.
> 
> - Start isearch again and observe that the faces are a mix of old an new. Most
>   notably are the background colors, which I'm trying to set to nil but which
>   are present in the newly created frame. The same for the foreground of
>   lazy-highlight. The box of lazy-highlight does appear, though.

Well, you should have said explicitly that the problem only happens
with colors that you set to nil.  If I missed that, I apologize for
not spotting that important detail.

What did you expect to happen as result of setting the color of a face
to nil?

And yes, for what (I think) you wanted to achieve, two calls that you
show in the OP are really necessary.