Answer
This is by design, not a permissions gap — per IFS's own documentation, the Object Property window is a system-administrator view-only screen: it shows existing object properties (driven by which modules are installed and their configuration) but doesn't support entering or editing anything directly through the client. The only thing that can be adjusted from this screen is whether validations are enabled for a given property (via the Validations Enabled checkbox and a validation method), not the underlying property values or records themselves.