When the value of the specified field evaluates to TRUE, the current business component becomes read-only.
The business component to be conditionally restricted is the one to which you add the user property as a child object definition. The business component containing the test field must be a parent or grandparent of the restricted business component by way of a link or series of link relationships.
Parent Read Only Field is used primarily to restrict the detail records in a multi-value group. It could also be used to restrict the detail records in a master/detail view, but in that case you need to make sure that the restricted business component is not also used in the context of some other business object than the intended one.
NOTE: When using the Parent Read Only Field user property, the test field must have its Link Specification property set to TRUE. Otherwise, the dynamic read-only functionality does not work. However, if the child record is displayed in the multi-value field in the parent business component, it is not necessary to have the Link Specification property of the field set to TRUE.
For more information on the Parent Read Only Field user property, see Configuring Siebel eBusiness Applications.