Sorry, I should’ve been more thorough (commenting out that line fixed the problem for me in my setup). I’ll try to get a complete recipe up.

> On Jun 17, 2016, at 12:21 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>  emacs -Q
>  (add-to-list 'load-path "/path/to/smart-mode-line-master")
>  (load-library "smart-mode-line")
>  (sml/setup)
>  (dolist (sym '(mode-line mode-line-inactive))
>        (set-face-attribute
>         sym nil
>         :box `(:line-width 2 :color ,(face-attribute `,sym :background))))