question: why spitfire solo strings violin virtuoso can't play fluat? [Solved]

Hi, everyone, I have a newbie question here. I'm new to the spirfire solo strings and may accidently touched something. Now my violin virtuoso can't play fluat. Moreover I saved the changed settings when I closed the window... What should I do now??

(just as the pictures show, there is no blue area when I choose flaut articulation)