Add or delete control point to curve not active

Device: ipad pro
I read and follow everything from this

  1. Select a curve and enter edit mode (single tap for one curve, double tap and select, then tap ‘Edit’ for more thane curve).
  2. Tap and hold anywhere along the dashed blue lines to ad a point. When the prompt to add a point appears, Tap it.
  3. A new control point has been added to the curve

But When tap and hold anywhere along the dashed blue line to ad a point or want to delete point , the prompt doesn’t appears!
How to fix this issue.

Hi @Khomson ,

Thank you for your patience.

I’m not sure why you don’t see the tooltip, when pressing & holding - are you doing it while using the Apple Pencil mode? Would you be able to upload a short video that shows what happens?