In the API docs, for the OnUpdateUiItem(type, state, data) event, it looks like "OBJECTPROPERTIES" is no longer a supported type (even though the JavaScript example has it as one of the switches). When you select an object, this event fires with type = "COMMAND" and data = "OBJECTPROPERTIES" (even though the COMMAND/OBJECTPROPERTIES is not documented). Still, it's not clear to me how to get to the object properties.
IMHO, the logical place for the object properties to show up would be when the OnSelectObject(objectNode, handled) event fires, but objectNode has no useful information--what type of an object is it in relation to the API docs? It doesn't have Properties hanging off of it.
thanks in advance, Chuck