The documentation says the 'diff' setting is local to window, so closing the windows show cancel the setting out, but when I try the below sequence on two related files say, x.old and x.new, it seems otherwise.
Vim seems to keep the 'diff' information around in the same way it keeps marks in a given file. Until it's unloaded, it still seems to remember it. Using :bw seems to obliterate the file so that the next time it is loaded you don't have 'diff' set.
I agree that the docs saying that 'diff' is per-window seems a bit misleading, as it seems to be per-buffer.
Just my $0.02 observation... -tim
