Scrolling a scrollview by dragging the bar

Hi, I have some ScrollViews with visible bars that I want to be able to scroll by dragging them. However, when I try to drag the bars, the inside content is dragged instead, so it goes in the opposite direction. How can I allow the bars to be dragged by the user and move the content correclty?

del_scroll.zip (286.0 KB)
Sorry, currently the engine does not monitor the scroll-bar, you can refer to this demo, which is a simple implementation based on version 2.4.3.