Kudos to @Soledad for providing perfect debugging information and for the smooth collaboration 🙂
I’ve found the root cause of the crash and was able to fix it. Please read on if you’re interested in details (some mumbo jumbo), an interims fix, and if you feel confident with using a pre-release via TestFlight:
The problem is caused by a curve element whose anchor point is identical to the control point defining the curve: When this control point is dragged (what happens as dragging control points has priority over anchor points), its 2nd corresponding control point is moved accordingly by default. Here my code was performing a zero division, causing an invalid point. Later on an Apple function crashes when drawing this invalid point.
I’ve just submitted the corrective update to Apple for review. Once approved I will make it available via TestFlight and announce it in a dedicated forum’s discussion.
In the meantime this issue can be circumvented by holding the <Alt> key when dragging the critical point: In this mode the corresponding control point isn’t moved...
