Hi,

Scrollbar that appears on hover is default behaviour for the Nanoscroller library script that is used in our theme. If you want to use default browser scroller without hover please disable Nanoscroller in Theme Setting => Perfomance => JS => Nanoscroller library.

Examples from Chrome browser:
Widget with nanoscroller – https://gyazo.com/3438508809b6640db3e9e0eb080b7d65
Widget without nanoscroller – https://gyazo.com/5dc437793afc3ef746ffcbb40b48f6a9

Best Regards