PropertyHandle :: Unlock - Unlock instance
This function allows unlocking the selected instance of the property handle after it has been locked (-> Lock()). Instances for shared base structures are not automatically included in the unlocking and must be unlocked separately when being locked separately.
The function returns NO when the instance has been unlocked successfully. It returns an error (YES) when the instance is not locked, when no instance is selected in the property handle or when another error occurred.
Return value: Success ( logical )