Hi.
There seems to be a bug with the scrolling bars on the MacOS app. When not in full screen mode clicking on a bar will make it jump ahead (horizontally or vertically) then the bar becomes unresponsive. So far, in full screen mode that is not happening and the bars can be dragged, no problem.
MacOS 10.15.7
Edit: Just checked again. It happens when using a usb mouse, not when using the trackpad.