You can protect objects against modifications if your lock level is greater than 0, if the objects you are trying to lock are not already locked, and if the page layer you are working on is not locked.
Select one or more objects, and then on the Layout menu, do one of the following:
•To lock, click Lock object(s).
•To unlock, click Unlock object(s).
Note
This operation locks only the geometry.
If the locked object is a linked frame, its content still can be modified in Fred4 and in Ted4
See also
Protecting paginated text against content modification