patch 8.0.0732: when updating a buffer modeless selection is lost commit https://github.com/vim/vim/commit/80dd3f9d41ce2ff6ab3544cdb266627bbdfc34a6 Author: Bram Moolenaar <Bram@vim.org> Date: Wed Jul 19 12:51:52 2017 +0200 patch 8.0.0732: when updating a buffer modeless selection is lost Problem: When updating a buffer for a callback the modeless selection is lost. Solution: Do not insert or delete screen lines when redrawing for a callback and there is a modeless selection.

" Vim indent file
" Language:	Mail
" Maintainer:	Bram Moolenaar
" Last Change:	2009 Jun 03

if exists("b:did_indent")
  finish
endif
let b:did_indent = 1

" What works best is auto-indenting, disable other indenting.
" For formatting see the ftplugin.
setlocal autoindent nosmartindent nocindent indentexpr=