Instead of boundary boxes, lines and connectors have small circles defining each endpoint and, in the case of connectors with more than two segments, one to control each middle segment. If you click on the line or connector anywhere but on these circles, you’ll move the entire line without changing its shape. Clicking and dragging the circles will move only that end of the line or connector. If you move the shape that a line or connector is linked to, the line or connector will adjust to maintain the connection.