           "<span style=\"color:#{color}\">#{value}</span>"
         ])
 
-      @node(html.join(""), children)
+      @node(html.join(""), "", children)
 
     isRef: (obj) ->
       _.isObject(obj) and (_.isEqual(_.keys(obj), ["id", "type"]) or

    isAttr: (attr) ->
      attr.length > 0 and attr[0] != '_'

    node: (text, children, open) ->
      text: text
      children: children or []
      state: { open: open or false }


          visited = {}
          visited[obj.id] = 1
          @descend(index, obj, visited)
        @node(type, "collection", children)

      if nonempty
        node for node in nodes when node.children.length > 0
