Sawfish provides extra tools and commands for dealing with ICCCM groups. Most "normal" groups work the same way as they do in the ICCCM standard: windows have a group property that is set to the X window ID of the group leader. These are "group IDs", and they are always positive integers. In addition, Sawfish allows group IDs to be:
| window-group-ids | Function |
| Return the list of all group ids. |
There may be certain named groups that always exist, whether or not any window belongs to them.
| peristent-group-ids | Variable |
| A list of symbols naming groups that always exist. |
In any case, a window is limited to belonging to one group, and always belongs to one group.