Whitespace under the cursor in vim

Question

I recently saw this demo. My question is: how is it possible in vim to show whitespace characters under the cursor as dots (in red for example).

Answer 1

I don't think that's showing space under the cursor; I think it's showing trailing spaces. This is controlled by the listchars option, which controls the behavior of list. To turn it on, use:

set list
set listchars=trail:·

The color is determined by the hl-SpecialKey group; you can change it like this:

hi SpecialKey ctermfg=Red