Comment 5 for bug 390641

Option --using on Windows requires full path to the diff application. I'd say probably bzr can't find your diff tool and fall back to internal implementation. I dunno.

I don't see the big problem with WinMerge, but I should note there is small problem. WinMerge is GUI diff tool, nevertheless bzr prints in the console name of changed file prefixed with 3 equal signs, e.g.

=== modified file 'foo.txt'

Perhaps I understand where from it come, but probably it should be possible to disable it.