Diagnosis
On the item overview, you have selected a number of items in order toenter sub-items for these items.
You are now looking at the detail screen of one of the selected itemsand want to get the detail screen of the previous item using functionItem-.
A table is used to determine whether you can maintain sub-items for anitem category. The item category of the previous selected item does notsupport sub-items.

Procedure
You can only enter sub-items for the previous selected item if theindicator for sub-items was set in table T418 (Item Status) for theitem category concerned. Consult the department responsible formaintaining this table to check whether this is feasible.