The issue is using putty ssh to a linux host ,let’s say Debian 10 , then use command VIM file to open a file , then type i to change to insert mode , then use right-click to paste something into vim , instead of pasting vim is changed to (insert) VISUAL mode.

Workarounds

  • For current user only

    Normally this issue happens when you don’t have ~/.vimrc file , so you can create one using below command, then re-open file using vim

    touch ~/.vimrc

  • System wide

    Above one fix the issue for current user only , to fix it in system-wide,uncomment below line from /etc/vim/vimrc

    let g:skip_defaults_vim = 1

    This will prevent vim sourcing file $VIMRUNTIME/defaults.vim if you don’t have ~/.vimrc file

  • Temporary workaround

    The reason is option set mouse=a is enabled , so you can fix it temporarily using below command inside vim:

    :set mouse=

    Or use keyboard shortcut:

    Shift+Ins(ert)

Wait ,but why

As mentioned above , right-click pasting not working is caused due to set mouse=a was enabled ,but how did it been enabled.

:help defaults.vim

You will get below after inputting above command in VIM

If Vim is started normally and no user vimrc file is found, the
$VIMRUNTIME/defaults.vim script is loaded

And for $VIMRUNTIME/defaults.vim ,it points to /usr/share/vim/vim81/defaults.vim

root@localhost:~# grep mouse /usr/share/vim/vim81/defaults.vim
" text scroll if you mouse-click near the start or end of the window.
" In many terminal emulators the mouse works just fine.  By enabling it you
" can position the cursor, Visually select and scroll with the mouse.
if has('mouse')
  set mouse=a

See, we found it. And that’s why we can fix this issue in system-wide by modifying file /etc/vim/vimrc