Connector lines

Okay, I was hoping these would work like powerpoint's: you run them between objects, and when you move the objects, the lines reroute themselves. This is of immense help in creating flow charts and the like.

But the ines will not stay connected to the shapes I connect them to. If they don't stay connected, what's the use of having them?

Is there something I'm not doing right?  Can the lines be edited after being laid down?