When I draw quickly or "flick" the curve line, it always start as a straight line, how long is how fast, and then proceeds with the curve stroke. The difference from previous update was when I experienced problem with straight lines and pen-pressure error, I'd had to restart my System's Wacom Tablet, then Shift-"pen-click" on the Krita starting screen. On this new 4.0, the pressure works perfectly fine, but the straight line came back. Even if I recalibrate with Shift-"Pen-click", it still comes back..
Could you check if this fixes it? https://docs.krita.org/Drawing_Tablets#Wacom_Double_Click_Sensitivity_.28Straight_starts_of_lines.29
1: It works; I have to set "Tip Double Click Distances" all the way to "Minimum" settings, but I don't know what it actually does. 2: I never had to lower double click sensitivity before I upgrade it to 4.0. Should I be concern about it?
It's a recent "improvement" in Wacom's drivers, not something we do anything with.