n {Object} [Tree node]
      */
      build: function (data) {
        var el = this;
        var tree = el._refs.tree;
        var treeNode, node, parent
        // Loop through nodes
        for (var index in data) {
          node = data[index];
          // Create tree node
          treeNode = document.createElement("vc-treenode");
          el._copyProperties(node, treeNode);
          // Append tree node
          tree.appendChild(treeNode);
        }
        // Return the last node for events purpos