This dialog appears if you do the following:
Use the Select Modules for Group "<group name>" dialog to view and select modules for a module group.
The list field displays all instances of modules currently running in the system.
The list field displays the modules currently selected for the <group name> group.
Adds the module selected in the All Items list field to the <group name> group.
Removes the module selected in the Selected Items list field from the <group name> group.