commit https://github.com/vim/vim/commit/2faa29f896252073b53f387406109e331fbbe5f8 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Jan 23 23:02:34 2016 +0100 patch 7.4.1161 Problem: ":argadd" without argument is supposed to add the current buffer name to the arglist. Solution: Make it work as documented. (Coot, closes https://github.com/vim/vim/issues/577)

" Simplistic way to make spaces and Tabs visible

" This can be added to an already active syntax.

syn match Space " "
syn match Tab "\t"
if &background == "dark"
  hi def Space ctermbg=darkred guibg=#500000
  hi def Tab ctermbg=darkgreen guibg=#003000
else
  hi def Space ctermbg=lightred guibg=#ffd0d0
  hi def Tab ctermbg=lightgreen guibg=#d0ffd0
endif