vi /usr/share/vim/vim80/defaults.vim set mouse=r It's
set mouse=r
I did edit the default file because there were more defaults changed since jessie.
vi /usr/share/vim/vim80/defaults.vim
because somehow now syntax highlighting was on at default and all the users complained.
Found on > https://unix.stackexchange.com/questions/341564/vim-unable-to-copy-paste-in-debian-stretch