{des3:78} An empty or missing role attribute means the group is a logical grouping and does not directly create a concrete object. Such logical grouping can be used by the user or the GUI to group objects together. For example -a rectangle could be stored as a group (with no role) of 4 lines. +the user may draw arrows using lines and polygons to represent some logical +relation between areas of a sheet; to be able to easier move/copy/delete an +arrow, the user may use a custom group hosting the arrow.
{des3:65} Note: a junction connecting different groups can be created only by a connection object.