In Debian/Stretch, the default ViM settings have been changed — for the worse, in my opinion.

However, undoing the bad settings is not a matter of fixing them in your ~/.vimrc, because when that file is detected no defaults at all are set.

The quick fix is to create a custom /etc/vim/vimrc.local file with the following settings:

" Instead of auto-sourcing this afterwards, source it now.
source $VIMRUNTIME/defaults.vim
let g:skip_defaults_vim = 1

" Now we undo the "wrong" settings.
set mouse=
set noincsearch
set nosi

(Adjust "wrong" settings as needed.)

This way you still get the Debian defaults, but can change those that aren't to your liking.

stretch vimrc debian vim