[syslinux] Question about set_background

[Loïc Grenié]

     I've traced the code of set_background quite a bit this w.e. and
  was wondering what would happen in the __unlikely case where
  there is no background for the main menu and one for a submenu.
  It looks to me that when the submenu is closed, set_background
  will be called with new_background == NULL, that
  current_background != NULL inside so that there will be a
  strcmp(current_background, NULL) inside the function.

    Thanks,

         Loïc Grenié