Yep, I know, "Search, don't sort," but it's annoying to want to find that e-mail from that one vendor rep, and you don't know whether he's a Geoffrey or a Jeffrey, or a Jeffery. Especially if you can only remember that his last name starts with an R or some other very, very popular lastname firstletter.
I just learned about Zimbra Desktop for the first time last week, and installed it as a possible replacement for TBird, which I like a lot, but has just a few idiosyncracies that drive me nuts, so I downloaded and installed the software. Very slick. But I was just gobsmacked to see that there's no sort by sender. Even that gawdawful OutHouse Express can sort by From!