I see, I don’t remember the specifics but indeed your pipeline does not execute when it should. By disabling the picking part, you may be tagging object as “not changing”. Without seeing how you setup your pipeline/widget it is hard to tell. The pointer change is to let the user know that it is an handle that can be grabbed. Anyhow, @Forrest might be able to help if you provide more information.
Also, your representation should update the actor directly (center) rather than recomputing the polydata of the sphere.