Restricted Built-ins affect navigation in your form, either external screen navigation, or internal navigation. You can call these Built-ins only from triggers while no internal navigation is occurring.
Restricted Built-ins cannot be called from the Pre and Post triggers, which fire when Oracle Forms is navigating from object to another.
Restricted Built-ins can be called from the When triggers that are specific to interface items, such as When-Button-Pressed or When-Checkbox-Changed. Restricted Built-ins can also be called from any of the When-New-"object"-Instance triggers and from key triggers.
Unrestricted Built-ins do not affect logical or physical navigation and can be called from any trigger.
The Built-in descriptions include a heading, Built-In Type, that indicates if the Built-in is restricted or unrestricted.