Qooxdoo TreeVirtual only returns expanded nodes as dataModel

when i do a this._tree.getDataModel(); in qooxdoo on a treevirtual, i only get back the expanded nodes. How can i get all node开发者_Go百科s in the tree?

I found a solution by my self. The getData() function provides an array of all nodes in the datamodel.

var dataModel = this._tree.getDataModel();
var dataArray = dataModel.getData();