The Attributes Tab

The Attributes tab in the Split View lists all attribute sets assigned to the item selected in the All Folders tree.  Sets can be expanded by clicking the [+] next to their names and collapsed by clicking the [-].  New sets can be added by clicking the [Add Set]  button and sets removed by clicking the [Delete Set] button (note: this does not delete the set definition just its association with the selected item and the values it holds for the item).  Attribute values can be edited and check boxes checked or unchecked.