I appreciate the tips and discussion.

(let ((pop-up-frames t))
  (pop-to-buffer " *string-pixel-width*"))

is identical to the wonky snippet, first showing the unwanted buffer then switching to the wanted buffer (and first paying the display cost for the original buffer).

On Sat, Jan 25, 2025 at 11:26 AM Eli Zaretskii <eliz@gnu.org> wrote:

> From: Ship Mints <shipmints@gmail.com>
> Date: Sat, 25 Jan 2025 10:47:27 -0500
> Cc: stefankangas@gmail.com, 75828@debbugs.gnu.org
>
> Because I want a guaranteed new frame with the explicitly specified buffer.

And pop-to-buffer cannot guarantee that?