I tried moving off thunderbird to just about every graphical open source client I could find but they were all missing some key threading functionality that I u

I tried moving off thunderbird to just about every graphical open source client I could find but they were all missing some key threading functionality that I use heavily. Particularly either 1. Show the discussion tree in my inbox and 2. Pull up the entire thread for a message in my inbox (or search or any other folder). I've stuck with Thunderbird because it doesn't have an major flaws. But it is definitely slow and clunky.