I see that someone else asked exactly the same question more than a year ago and received no answer, which is not encouraging.

The connectors in a hierarchical Smart Art slide are locked, apparently by default. Here's what is happening:

I created a built-in Smart Art graphic, org chart-style. I selected one box and selected from the menu "Add shape below." The added shape is quite large and the connector goes from the bottom center of the first shape to top-left corner of the added one. I want it to go to the center. That seems simple and obvious enough, but I'm stumped.