Client-side browsing for data|OPC UA Standard|Forum|OPC Foundation

In our UA client toolkit, we have a bunch of UI controls for browsing. 

Recently, a user has complained about the fact that our UI does not show all the nodes. He had provided an example of UaExpert screen where more nodes could be seen – within a Prosys simulation server. Upon investigation, I have found that the nodes in question have a custom “HasSignal” reference, which is a direct subtype of Aggregates reference type.

The purpose of our UI controls is to browse for nodes that are meant by the server vendor to be read from/subscribed to/written to. As such, the browse controls/dialogs do not expose the full content of server’s address space. They are meant to be integrated to apps like HMIs, loggers etc. For that reason, the browsing functionality in these UI controls differs, with some simplification, from the “show everything” approach in following aspects:

1. The browsing starts in the Objects folder, and not in the Root.
2. The only node classes displayed are Objects and Variables.
3. The reference types followed are only: a) “Organizes” and its subtypes, and b) “HasComponent” and its subtypes, c) HasProperty and its subtypes (optionally, if we want to show Properties).

Because the custom “HasSignal” reference type in Prosys simulation server is a subtype of neither Organizes nor HasComponent nor HasProperty, we do not display it in browsing.

Is this behavior on client side correct? In my opinion, for this type of client, it is – but I am seeking some confirmation. I believe that if the server vendor wanted these nodes be shown by clients such as ours, they should have made the reference type a subtype of HasComponent.

Or, should we rather widen our filter by allowing Aggregates and its subtypes?

Thank you