What Insert Slicer offers: the fields a slicer can filter by, and the one the active cell is in, which a press filters by.
Readonly
The field the active cell is in; null when it is in none, as on a pivot table's values.
null
A table's column names, or a pivot table's field names, in order.
What Insert Slicer offers: the fields a slicer can filter by, and the one the active cell is in, which a press filters by.