I have tried Krita as well as Gimp. Same issues, though the random straight line seems to happen less frequently. I had disabled all other devices for painting in MyPaint already since I kept accidentally drawing with my palm. I don’t think multi touch is enabled at all? At least I can’t find any settings and nothing seems to happen if I try anything, though I have to admit I usually don’t use tablets.
Under Windows 10, I don’t have the straight lines and jagged edges, but no pressure sensitivity, and it’s also a bit laggy. MyPaint only shows the system pointer as a device. The sketch app that comes with Windows works fine, though, so it’s not an issue with the pen itself.
I will try MyPaint 1.0 next, thanks for the suggestion!
