如何在滚动查看器中获取滚动条以在单击时聚焦滚动查看器？

Currently with a scrollviewer, clicking the scroll bar contained in it to pan the content around it will not focus the viewer (or anything for that matter). I wish to have it so when you scroll by dragging the scroll, or even clicking the scrollbar will focus the parent (scroll viewer).Currently with a scrollviewer, clicking the scr