Going to add to this as well. I can affirm that I'm having similar difficulties as of 7/7/19 - works for a bit, then not, pan not working, brush only makes straight lines made, etc.
Adding - the "High Precision Tablet input" (Preferences> Tools) messes with the input screen area. The screen IS set up correctly for this monitor - I get near the left toolbar and... zip, my cursor is on the right side of the monitor? Whaaaaat? Turning this off fixes the problem.
I appreciate the team working on this issue, but I'm not enjoying being "locked" onto one monitor. FYI - the only thing i had on a second monitor was the Layers Pallet. :O
Huion H1060P w/ battery free pen / (3) monitors / Both huion drivers and Photo & Designer 1.7.1.404 have the latest updates.