commit https://github.com/vim/vim/commit/864293abb72d62604d8d6b458addfb43c14230c3 Author: Bram Moolenaar <Bram@vim.org> Date: Thu Jun 2 13:40:04 2016 +0200 patch 7.4.1871 Problem: Appending to the quickfix list while the quickfix window is open is very slow. Solution: Do not delete all the lines, only append the new ones. Avoid using a window while updating the list. (closes #841)

README_src.txt for version 7.4 of Vim: Vi IMproved.

The source archive contains the files needed to compile Vim on Unix systems.
It is packed for Unix systems (NL line separator).

For more information, see the README.txt file that comes with the runtime
archive (vim-7.4-rt.tar.gz).  To be able to run Vim you MUST get the runtime
archive too!