bug#54196: 29.0.50; flat-button face box style does not work as expected

[David Ponce]

On 28/02/2022 10:58, Lars Ingebrigtsen wrote:
> David Ponce <da_vid@orange.fr> writes:
>
> > I noticed that the :box :style flat-button is not working as expected:
> > the line around the text seems to be there, but not visible.
> >
> > Just evaluate the below code in the scratch buffer will show the
> > problem:
> >
> > (insert
> >   (propertize "This buffer is for text"
> >              'font-lock-face
> >              '( :box ( :line-width (4 . 4)
> >                        :color "dark grey"
> >                        :style pressed-button)))
> >   "\n"
> >   (propertize "This buffer is for text"
> >              'font-lock-face
> >              '( :box ( :line-width (4 . 4)
> >                        :color "dark grey"
> >                        :style released-button)))
> >   "\n"
> >   (propertize "This buffer is for text"
> >              'font-lock-face
> >              '( :box ( :line-width (4 . 4)
> >                        :color "dark grey"
> >                        :style flat-button)))
> >   "\n"
> >   )
>
> I'm not sure what I'm supposed to be looking for here.  Can you include
> some screenshots and point to what you think is the problem?
My example above to illustrate the issue, inserts 3 lines with the same text in 
the scratch buffer:

1st line with a gray pressed-button box around the text. Work as expected.
2nd line with a gray released-button box around the text. Work as expected.
3rd line with a gray flat-button box around the text. Doesn' work as expected. 
The gray line around the text is not visible.

I attached a screen shot.

face-box-screenshot.jpg
Description: JPEG image