mark "active" node of cutline
by changing its color or shape or something. User likes to know which point he is about to delete.
The active node is visible when you point the mouse cursor on it but we will review the idea and implement the color change.
To exit this mode is easy by clicking on the other panel (Overlay e.g.).
To improve this feature, please feel free to be more specific.
Nick Armstrong commented
Also, make it clear how to exit the cutline drawing mode. I had a problem exiting this mode.