Roundcube seems to own it. Not that many Foss clients to choose from, and RC seems most robust. The only feature I've ever longed for is a simple way to includ

Roundcube seems to own it. Not that many Foss clients to choose from, and RC seems most robust. The only feature I've ever longed for is a simple way to include a non-reply email in another email message. There's probably a plugin for it.