VIM conceal doesn't work

Question

VIM doesn't conceal text, for example tex. Here's my vimrc:

"commands for vim-plug 
"PlugInstall - installs plugs  
"PlugUpdate - updates plugs 
"PlugClean - remove unused directories 
"PlugUpgrade - upgrades vim-plug itself 
"PlugStatus - status of plugs
"vim-plug installer

if empty(glob('~/.vim/autoload/plug.vim'))
    silent !curl -fLo ~/.vim/autoload/plug.vim --create-dirs
        \ https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim
        autocmd VimEnter * PlugInstall --sync | source $MYVIMRC
    endif

call plug#begin('~/.vim/plugged')

Plug 'itchyny/lightline.vim' "lightline
Plug 'altercation/vim-colors-solarized' "solarized theme
Plug 'scrooloose/nerdtree' "NERDTree
Plug 'scrooloose/nerdcommenter' "NerdCommenter
Plug 'majutsushi/tagbar' "tagbar
Plug 'lervag/vimtex' "for latex 

call plug#end()

set encoding=utf-8

"settings for lightline 
set laststatus=2 "displays lightline
set noshowmode "vim's mode is not show belove lightline 

"changes colorscheme
let g:lightline = { 
    \ 'colorscheme': 'solarized', 
    \}

"settings for colorscheme 
"after installing
"$ cd vim-colors-solarized/colors
"$ mv solarized.vim ~/.vim/colors/
colorscheme solarized
set background=dark 

"settings for NERDTree
"autocmd vimenter * NERDTree "opening NERDTree with every vim start
nmap <F8> :NERDTreeToggle<CR>
autocmd bufenter * if (winnr("$") == 1 && exists("b:NERDTree") && b:NERDTree.isTabTree()) | q | endif "closing NerdTree i

nmap <F9> :TagbarToggle<CR>

let g:tex_flavor='latex'
let g:vimtex_view_method='zathura'
set conceallevel=2
let g:tex_conceal='abdmg'
"-------------------------------------------------------------------------------------------------------------
"                                             no-plug setup 
"-------------------------------------------------------------------------------------------------------------

"split navigation CTRL + H/J/K/L
nnoremap <C-J> <C-W><C-J> 
nnoremap <C-K> <C-W><C-K>
nnoremap <C-L> <C-W><C-L>
nnoremap <C-H> <C-W><C-H>

syntax enable 
set tabstop=4 "number of visual spaces per TAB 
set shiftwidth=4
set softtabstop=4 "number of spaces in TAB when editing 
set expandtab " TABs are spaces 
filetype indent on 
filetype plugin on
autocmd FileType cpp setlocal commentstring=//%s
set showmatch 
set splitbelow
set splitright
set lazyredraw
set wildmenu

set hlsearch
set incsearch
nmap <silent> ,/ :nohlsearch<CR>

" space open/closes folds
nnoremap <space> za

set foldmethod=manual
augroup remember_folds
    autocmd!
    autocmd BufWinLeave * mkview
    autocmd BufWinEnter * silent! loadview
augroup END

"line numbers
set number relativenumber

augroup numbertoggle
autocmd!
autocmd BufEnter,FocusGained,InsertLeave * set relativenumber
autocmd BufLeave,FocusLost,InsertEnter   * set norelativenumber
augroup END

"it's finnaly time to learn hjkl
map <up> <nop>
map <down> <nop>
map <left> <nop>
map <right> <nop>

With khzaw/vim-conceal conceal works in python.

any ideas?

Answer 1

You should remove augroup remember_folds commands

Answer 2

The reason removing augroup remember_folds helped was given here: https://github.com/vim/vim/issues/4175. Basically neither mkview nor loadview remember filetype nor syntax. Quick fix to that problem is modyfing those commands. The augroup remember_folds should look like this:

augroup remember_folds
    autocmd!
    autocmd BufWinLeave ?* mkview | filetype detect
    autocmd BufWinEnter ?* silent loadview | filetype detect
augroup END