Extended properties..

[Hippocode 18]

From the advanced object example in testermodule there is an object that can be on more then one layer which I thought it wasn't possible.

It loads extended properties but I can't find any info about on http://developer.vectorworks.net/index.php/SDK:Parametric_Extended_Properties

EObjectEvent CObjAdvComplex_EventSink::OnInitXProperties(CodeRefID objectID)
{
// obtain the interfact for accessing the extended properties
using namespace VectorWorks::Extension;
VCOMPtr	extProps( IID_ExtendedProps );

extProps->SetObjectProperty( objectID, kObjXPropSupportProxyObjects, true );

return kObjectEventNoErr;
}

It also uses a function not listed anywhere

gSDK->GetProxyParent( fhObject );

I'm not interested in this particular function but I'm wondering if there are more unlisted functions like this..