When the pop up menu automatically appears and I press `Ctrl + S`. It pastes `:w`?

Question

I'm using an Auto Completion Pop Up script.

When I place the cursor

left:(here) 218px !important;

or

left: (here) 218px !important;

the pop up menu automatically appears as usual, then I press Ctrl + S and it pastes :w. I think it is trying to complete : for :w.

Any suggestions to fix this?

I have this in my vimrc:

" Use CTRL-S for saving, also in Insert mode
noremap <C-S> :w<CR>
vnoremap <C-S> <C-C>:w<CR>
imap <C-S> <C-O>:w<CR>

Answer 1

Using <Esc> instead of <C-O> solved the problem.

noremap <C-S> :w!<CR>
vnoremap <C-S> <Esc>:w!<CR>
inoremap <C-S> <Esc>:w!<CR>

Answer 2

The Auto Completion script provided there doesn't work for me so I can't give a correct way to actually fix the problem, but as far as I can tell the issue is as follows.

The CTRL+S command that you use doesn't do anything more than enter :w followed by Carriage Return in vim's Normal Mode. :w + Enter is the actual way of saving a file in vim, your CTRL+S is a shortcut to that.

I'm led to believe that that pop up plugin somehow prevents the shortcut to make a quick switch to normal mode, thus inserting :w into your actual document.