When you highlight text on paper you are changing the background colour. That's the definition of highlighting. That's also the definition in pretty much all the word processor/text display programs I have ever seen. If what you are saying is you want to change the text colour then use ForeColor instead of BackColor in the code I posted above.
Got you. Like selecting "doc" in "indoctrinate" would result in only "doc" being highlighted. I don't think you can get that type of granularity in that control. I might have got that sooner if I'd had more than 3 hours sleep in the last 24 hours.