& has column headers, which will also be deleted

What causes this issue?

You are on the "Table Control Attributes" screen and want to reset the
"With column headings" attributes.
The table control already contains column heading elements.

System Response

If you continue, the system deletes all of the column heading elements
belonging to the table control.
If you are in modification mode, the system only deletes those column
heading elements that you created in modification mode.

How to fix this error?

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

Error message extract from SAP system. Copyright SAP SE.