How is it advisable to draw 3D polylines to avoid errors when clicking on points in different planes?
Indeed, it is risky to know where you are clicking when you are drawing on the point cloud. The best thing to do before drawing is to graphically select the area of interest using a rectangle as narrow as possible, and restrict the cloud so that only these points are visible.
From version 1.4, you can define a plane by means of three points is foreseen, so that vertices are drawn without leaving it. Watch https://youtu.be/Ntur-_E_Wmw