Comment 4 for bug 490212

I trigger diff with an external tool mostly through the Explorer GUI, qcommit or qlog, where I wouldn't have the opportunity to specify the command-line option. So I think a GUI option will be required, but the command-line option is a good first step to make sure stuff works first.

I think the option should be described/named in terms of showing diffs one-at-a-time or all-at-once, since that's what it does. "GUI mode" vs "CLI mode" won't make much sense to most users.