Select an area to be copied

What causes this issue?

To perform the "Copy" function, you must first select an area.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

The following areas can be copied:
entire rows
entire columns except lead columns and
blocks which lie completely in either a row or a column and outside of
the area of the lead columns.
You can select either using the Select functions, or the corresponding
icons, or implicitly by positioning the cursor.
The cursor position is interpreted as follows:
Cursor is placed in the area of the lead columns
then the row in which the cursor is placed is regarded as selected
Cursor is placed in a data cell outside the lead columns
then the data cell is regarded as selected.

Error message extract from SAP system. Copyright SAP SE.