Curt wrote: > Maybe that lead-in violates some RFC, although you'd think what's in the > header's in the header and what ain't ain't and ne'er the twain shall > meet. > > At any rate, bw threads fine here, so it must be you (or me). It's you -- or rather bw's MUA, I'm afraid. :-) His mails don't thread in neomutt neither, specifically because the headers sent by his MUA don't include neither the Reference nor the In-Reply-To fields. Thomas