This window enables the changing of the session statistics used by the corresponding columns in the Session Details window. You can select statistics and select whether the cumulative or delta value should be used.
For convenience, there are a few predefined statistics out of all the other standard statistic classes in v$statname:
All available statistics are grouped into classes as defined by Oracle in v$statname.CLASS: User, Redo, Enqueue, Cache, OS, Parallel Server (RAC), SQL, Debug (see also Oracle Database Reference).
Please remember there are two Session Statistic columns in the Session Details window, and they can only be changed one at a time.