[ruffel]

Select two commits. Edit Commit -> Squash Selected Commits, ignoring new messages (fixup)

[globular-toast]

That's not a fixup commit, it's a rebase. It's missing the point of fixup commits which is to commit now and defer the rebase until later.

It's also completely missing the point of the feature under discussion here which is to automatically decide which commit to squash the fix into.