Hey,
We have a component, see below. There are nodes A, B, and C, I want to let node B move simultaneously when moving node C, which like moving group node and its children get moved.
Try overriding DraggingTool.computeEffectiveCollection
DraggingTool | GoJS API
to first call the super method, then notice if C is in the returned Map, and if so add B to the Map with a new DraggingInfo that has B’s Node.location, and finally return that Map.