Grey bar on left in vim?

Question

I get a grey bar on left side in vim for one file. This does not happen for any other file. What is this? And how to get rid of it?

EDIT:

This is what it looks like: This goes on for the full height of the file. It does not appear in any other files. The file is a *.C which is correctly identified as of cpp file type but this thing does not happen to other files where they are being identified as cpp. colourscheme is default

EDIT2: Here is the view file for the file:

let s:so_save = &so | let s:siso_save = &siso | set so=0 siso=0 argglobal setlocal keymap= setlocal noarabic setlocal autoindent setlocal nobinary setlocal bufhidden= setlocal buflisted setlocal buftype= setlocal cindent setlocal cinkeys=0{,0},0),:,0#,!^F,o,O,e setlocal cinoptions= setlocal cinwords=if,else,while,do,for,switch setlocal comments=s1:/*,mb:*,ex:*/,://,b:#,:%,:XCOMM,n:>,fb:- setlocal commentstring=/*%s*/ setlocal complete=.,w,b,u,t,i setlocal completefunc= setlocal nocopyindent setlocal nocursorcolumn setlocal nocursorline setlocal define= setlocal dictionary= setlocal diff setlocal equalprg= setlocal errorformat= setlocal expandtab if &filetype != 'cpp' setlocal filetype=cpp endif setlocal foldcolumn=2 setlocal foldenable setlocal foldexpr=0 setlocal foldignore=# setlocal foldlevel=0 setlocal foldmarker={{{,}}} setlocal foldmethod=diff setlocal foldminlines=1 setlocal foldnestmax=20 setlocal foldtext=foldtext() setlocal formatexpr= setlocal formatoptions=tcq setlocal formatlistpat=^\\s*\\d\\+[\\]:.)}\\t\ ]\\s* setlocal grepprg= setlocal iminsert=0 setlocal imsearch=0 setlocal include= setlocal includeexpr= setlocal indentexpr= setlocal indentkeys=0{,0},:,0#,!^F,o,O,e setlocal noinfercase setlocal iskeyword=@,48-57,_,192-255 setlocal keywordprg= setlocal nolinebreak setlocal nolisp setlocal nolist setlocal makeprg= setlocal matchpairs=(:),{:},[:] setlocal nomodeline setlocal modifiable setlocal nrformats=octal,hex setlocal nonumber setlocal numberwidth=4 setlocal omnifunc= setlocal path= setlocal nopreserveindent setlocal nopreviewwindow setlocal quoteescape=\\ setlocal noreadonly setlocal norightleft setlocal rightleftcmd=search setlocal scrollbind setlocal shiftwidth=4 setlocal noshortname setlocal smartindent setlocal softtabstop=0 setlocal nospell setlocal spellcapcheck=[.?!]\\_[\\])'\"\    \ ]\\+ setlocal spellfile= setlocal spelllang=en setlocal statusline= setlocal suffixesadd= setlocal swapfile setlocal synmaxcol=3000 if &syntax != 'cpp' setlocal syntax=cpp endif setlocal tabstop=4 setlocal tags= setlocal textwidth=0 setlocal thesaurus= setlocal nowinfixheight setlocal nowinfixwidth setlocal nowrap setlocal wrapmargin=0 let s:l = 75 - ((20 * winheight(0) + 29) / 59) if s:l < 1 | let s:l = 1 | endif exe s:l normal! zt 75 normal! 0 let &so = s:so_save | let &siso = s:siso_save doautoall SessionLoadPost " vim: set ft=vim  

Answer 1

:set foldcolumn=0

Answer 2

In my case, no others but below was the solution.

set signcolumn=no