> I check &diff in my vimrc to set various settings specifically when doing a > diff/merge. Hi Andrew, could using an auto command on the "DiffUpdated" event work for you? Example: add this to .vimrc: au DiffUpdated * if &diff | colorscheme darkblue | endif This function will be executed every time "diff mode" is updated in any way and seems to work both when running vimdiff directly and when entering diff mode interactively (as it is the case now when running "git mergetool"). It has the added benefit that you can also use this same "trick" to toggle the settings off when *exiting* diff mode: au DiffUpdated * if !&diff | colorscheme desert | endif Let me know if this is enough for your use case. Thanks!