Message SAP WXPB218 - Function cannot be executed in lead columns

Diagnosis
The cursor is positioned on a lead column. The function selected cannotbe executed in this column.

System Response
If you want to switch on or off the lock for a value, position thecursor on the required data cell, subtotal or total.
If you want to switch on or off the readiness for input of a total,position the cursor on the required subtotal or total.