The Magnets Inspector is used to control magnets on shape, polygon and text objects as well as the connection behaviors of objects and groups.
In the Magnets Inspector you can add/remove and position magnets on objects, control whether an object allows connections, and control where on a group connections will be made.
Magnets on the currently selected shape are displayed in the magnets viewer window. You can zoom the viewer window in and out by using the zoom slider along the left side.
To add a magnet, click the plus button and a new magnet will appear in the center of the magnets viewer window. You can then drag the new magnet to the desired position on the shape. To delete a magnet, click on the magnet you wish to delete and then click the minus button.
You can also add magnets to an object by clicking on one of the magnet preset buttons. If you hold shift down you can click on more than one preset to combine them on the shape.
The Allow Connections checkbox toggles whether an object can connect to another object or be connected to.
You can temporarily disable connections when drawing a line by holding down the option key.
When you have a group selected you can choose whether lines will connect to the group itself or to the components that make up the group.