I'd like to be able to choose a color for either a "senders" emails & also be able to choose a color for an emails subject line. Such as be able to have all emails with (for example) "Thunderbird" in the subject line have it be highlighted whatever color I choose. As well as be able to have all emails (for example) with the sender being from "Thunderbird" to have it highlighted in the color of my choosing. And when choosing these options any and all emails whether already saved or new and/or incoming meeting that criteria selected would be highlighted in the chosen color. Incredimail used to have this feature and i found it very helpful organizing my emails.