Making virtualedit a local option

virtualedit is a global option. This means that when you call setlocal virtualedit it's not set just for this buffer but for all windows and all buffers. This is confusing, but only options labeled local to buffer in help can be set to the local buffer. virtualedit is labeled as global.

However there is a hack. You can simulate this as a buffer local option by setting it on BufEnter and unsetting it on BufLeave.

In my .vimrc.local I have

autocmd BufNewFile,BufRead,BufEnter *.part setlocal virtualedit+=all
autocmd BufLeave *.part setlocal virtualedit-=all

Set it when you enter, unset it when you leave, and now the setting is confined to the buffer you'd like to use it in.