Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: Radeon (TM) RX 480 Graphics ATI Technologies Inc. 4.5.13559 Core Profile Context 26.20.12001.11014
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
Short description of error
Scroll bar doesn't work on active window. If I open two instances it works only in the other window. In the active window it doesn't work using Wacom tablet.
Exact steps for others to reproduce the error
Open two instances of Blender and try to use Scroll bar with a Wacom tablet.
It happens at any time, it doesn't need an specific .blend file.