I use a touch screen monitor, but whenever I try to paint or draw something, the app doesn't registure and it just draws a line straight to the bottom of the screen. It used to just have a delay until it registured, but the shape tools work fine with it and Photoshop works just fine. It's just Animate CC
I've discovered it has something to do with my Pen Tablet app on my Huion moniter. For some reason the apps are conflicting somehow
I believe there's a conflict in Windows with drawing tablets due to a screen magnification feature/setting. Look into "WinTab" and Windows Pen settings. There may be a system display setting that you need to change.