Position of Anchor Point at Creation
When connecting two objects in the diagram editor with a link, there are two different behaviors which will position the anchor point on the shape.
The behavior to be used with a shape can be set in the shape editor.
 
From
To
Centered
The anchor point is centered in the shape
Targeting the green dots will change the style (orthogonal/straight) and orientation of the link
Free
The anchor point is positioned where the mouse is clicked or released
The default line style is used