What is the blue dot next to the part on the canvas for?
The blue dot is your gateway to having full control over the parts on the canvas. Think of the blue dot as a virtual handle for that part. When you click and hold your mouse on the blue dot you can click and drag it anywhere on the Rx canvas to different teeth it can apply to. When the blue dot is clicked and dragged to the opposing arch the part moves to that arch. You can also delete the part by dragging the blue handle off the canvas and it deletes immediately.