commit https://github.com/vim/vim/commit/0ba75a9714884895b2ac09733158c47544a8dfb9 Author: Bram Moolenaar <Bram@vim.org> Date: Fri Feb 19 23:21:26 2016 +0100 patch 7.4.1360 Problem: Can't remove a callback with ch_setoptions(). Solution: When passing zero or an empty string remove the callback.

Test for search('multi-byte char', 'bce')

STARTTEST
:source small.vim
:source mbyte.vim
:set encoding=utf-8
:/^Test bce:/+1
:$put =search('Ａ', 'bce', line('.'))
:1;/^Results:/,$wq! test.out
ENDTEST

Results:

Test bce:
Ａ