Cannot edit object, it is locked in different requests

What causes this issue?

The objects you are editing are locked in different requests.
You cannot edit objects in different requests at the same time.

System Response

The function terminates.

How to fix this error?

Make sure that all the objects that you are editing are in the same
request and repeat the action.

Procedure for System Administrators

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.