bug#59547: 28.2; The bottom border is not displayed when setting the pixel height of a child frame smaller than 1 line

[martin rudalics]

> The use case is to create a child frame with a height smaller than the
> default line height, because the character size in the child frame is
> set smaller than the default. How can this be achieved? Thanks.

Why don't you specify an appropriate font parameter like say

          (make-frame
           `((parent-frame . ,(window-frame))
             (font . "-PfEd-DejaVu Sans 
Mono-regular-normal-normal-*-04-*-*-*-m-0-iso10646-1")
             (no-accept-focus . t)

martin