Pixel distance from the cursor (smaller wins ties before z-order).
Optionaldraggable
draggable?:boolean
Arm a drag on press. Price lines set cursor: 'ns-resize' and move on one
axis; anything that moves on both (a drawing anchor, a whole shape)
declares it here, and the drag callbacks receive time as well as price.
Pixel distance from the cursor (smaller wins ties before z-order).