When the vertical scrollbar is visible, not in focus, and the user drags its thumb?

当垂直滚动条是可见的，而不是在焦点，用户拖动的拇指？

youdao

When the vertical scrollbar is visible, not in focus, and the user drags its thumb?

当垂直滚动条是可见的，而不是在焦点，用户拖动的拇指？

youdao