All the structural and state information on a group--that is, its label, icon, plinth, secondary state modifiers, and alarm balloon--are gathered into what is called the information cluster of the group.

This cluster is positioned by placing a reference decoration at the center of the group. The reference decoration is listed below and is applied in the given order:

The center of the group is the center of the rectangle for a rectangular group, the gravity center for polygonal groups, and the midpoint of the middle segment for linear groups.

You can modify the default positioning of the group information cluster by setting its relative position as an offset.

When a transformer is applied to the group, that is, when it is moved or scaled, the same transformer is applied to the offset of the group information cluster. In other words, the cluster follows the group. This is true regardless of whether the cluster position was specified with absolute or relative coordinates.

However, when the shape of the group is changed or the group is moved, the transformation of the group shape is not guaranteed to be affine. As a result, this change in the group shape is likely to change the default position of the group information cluster. You can specify whether such a shape change will affect the cluster position or whether the cluster will keep the same absolute coordinates. The property pinDecorations determines whether the position of the group information cluster is considered relative to the default position and will thus change if the default value changes.

You can define the above characteristics using CSS, with the following properties:

The characteristics of the plinth decoration that is added to the group graphic representation can also be customized, using the following properties: