How to find why esc doesn't work right away in visual mode?

Question

When I press <Esc> in visual mode, I don't immediately return to normal mode (the selection persists). I think that is because I have a mapping defined in visual mode shat starts from <Esc>. I tried doing the following to find that mapping:

:redir! > vim_keys.txt
:silent verbose map
:redir END

But there are no mappings that start with <Esc>:

v  ["          *@:<C-U>exe "normal! gv"|call search('\%(^\s*".*\n\)\%(^\s*"\)\@!', "bW")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
n  ["          *@:call search('\%(^\s*".*\n\)\%(^\s*"\)\@!', "bW")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
v  []          *@m':<C-U>exe "normal! gv"|call search('^\s*endf*\%[unction]\>', "bW")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
n  []          *@m':call search('^\s*endf*\%[unction]\>', "bW")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
v  [[          *@m':<C-U>exe "normal! gv"|call search('^\s*fu\%[nction]\>', "bW")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim n  [[          *@m':call search('^\s*fu\%[nction]\>', "bW")<CR> Last set from /usr/share/vim/vim80/ftplugin/vim.vim
v  ]"          *@:<C-U>exe "normal! gv"|call search('^\(\s*".*\n\)\@<!\(\s*"\)', "W")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
n  ]"          *@:call search('^\(\s*".*\n\)\@<!\(\s*"\)', "W")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
v  ][          *@m':<C-U>exe "normal! gv"|call search('^\s*endf*\%[unction]\>', "W")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
n  ][          *@m':call search('^\s*endf*\%[unction]\>', "W")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
v  ]]          *@m':<C-U>exe "normal! gv"|call search('^\s*fu\%[nction]\>', "W")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
n  ]]          *@m':call search('^\s*fu\%[nction]\>', "W")<CR>
    Last set from /usr/share/vim/vim80/ftplugin/vim.vim
v  <C-Z>       * <Nop>
    Last set from ~/.vimrc
n  <Space>     * zR
    Last set from ~/.vimrc
n  ,bd         * :Bclose<CR>
    Last set from ~/.dotfiles/.vim/plugin/bclose.vim
   ,             <Plug>(easymotion-prefix)
    Last set from ~/.vimrc
n  ,gl         * :!git log<CR>
    Last set from ~/.vimrc
n  ,gp         * :!git push<CR>
    Last set from ~/.vimrc
n  ,gc         * :!git commit -m '
    Last set from ~/.vimrc
n  ,ga         * :!git add
    Last set from ~/.vimrc
n  ,gs         * :!git status<CR>
    Last set from ~/.vimrc
n  ,rs         * :so $MYVIMRC<CR>
    Last set from ~/.vimrc
n  ,rr         * :vsplit $MYVIMRC<CR>
    Last set from ~/.vimrc
n  ,sc         * :SessionClose<CR>
    Last set from ~/.vimrc
n  ,ss         * :SessionSave<CR>
    Last set from ~/.vimrc
n  ,sl         * :SessionList<CR>
    Last set from ~/.vimrc
n  =A          * gg=G<C-O><C-O>
    Last set from ~/.vimrc
n  H           * ^
    Last set from ~/.vimrc
n  L           * $
    Last set from ~/.vimrc
n  Q           * :q<CR>
    Last set from ~/.vimrc
v  gx            <Plug>NetrwBrowseXVis
    Last set from /usr/share/vim/vim80/plugin/netrwPlugin.vim
n  gx            <Plug>NetrwBrowseX
    Last set from /usr/share/vim/vim80/plugin/netrwPlugin.vim
o  p           * i(
    Last set from ~/.vimrc
v  <Plug>NetrwBrowseXVis * :<C-U>call netrw#BrowseXVis()<CR>
    Last set from /usr/share/vim/vim80/plugin/netrwPlugin.vim
n  <Plug>NetrwBrowseX * :call netrw#BrowseX(expand((exists("g:netrw_gx")? g:netrw_gx : '<cfile>')),netrw#CheckIfRemote())<CR>
    Last set from /usr/share/vim/vim80/plugin/netrwPlugin.vim
n  <F2>        * :wq<CR>
    Last set from ~/.vimrc
n  <F1>        * <Nop>
    Last set from ~/.vimrc
n  ´           * :set list!<CR>:echo "List is ".&expandtab<CR>
    Last set from ~/.vimrc
n  ³           * :set expandtab!<CR>:echo "Expand tab is ".&expandtab<CR>
    Last set from ~/.vimrc
n  ö           * :vs<CR>
    Last set from ~/.vimrc
n  ó           * :%s/
    Last set from ~/.vimrc
n  ÷           * :set wrap!<CR>
    Last set from ~/.vimrc
n  î           * :tabnext<CR>
    Last set from ~/.vimrc
n  ð           * :tabprevious<CR>
    Last set from ~/.vimrc
n  ì           * :!ls<CR>
    Last set from ~/.vimrc
n  æ           * :Grep
    Last set from ~/.vimrc
n  å           * :e
    Last set from ~/.vimrc
n  ï           * :b
    Last set from ~/.vimrc
n  ô           * :call ReportFileSaveMark()<CR>
    Last set from ~/.vimrc

How do I find out why my Vim doesn't immediately exit visual mode when I press <Esc>?

Answer 1

It's possible that you had a mapping in visual mode whose {lhs} produces a sequence of key codes beginning with Escape. You can check what is the sequence of key codes produced by a key by pressing on the command-line:

C-v <key>

For example, on my machine, F1 produces:

^[OP

^[ is the caret notation of the Escape key.

If you have a visual-mode mapping whose {lhs} is F1, when you press Escape in visual mode, Vim may wait for OP to come.

You can tweak the amount of time Vim waits for a sequence of key codes to complete with the option 'ttimeoutlen'. By default, its value is -1, which means that Vim uses the value of 'timeoutlen'.
This other option controls the amount of time Vim waits for the {lhs} of a mapping to complete. The default value of the latter is 1000ms.

The help at :h 'ttm suggests the following command:

:set timeout timeoutlen=3000 ttimeoutlen=100
     ├─────┘ ├─────────────┘ ├─────────────┘
     │       │               └ wait 0.1s for a sequence of key codes to complete
     │       │
     │       └ waits 3s for a mapping to complete
     │
     └ don't wait indefinitely for the `{lhs}` a mapping or a sequence of key code to complete