+ void slotSortRoleChanged(const QByteArray &role);
+
+ /**
+ * Updates the state of the 'Group Ascending/Descending' action.
+ */
+ void slotGroupOrderChanged(Qt::SortOrder order);
+
+ /**
+ * Updates the state of the 'Group by' actions.
+ */
+ void slotGroupRoleChanged(const QByteArray &role);