The nodes of this tree are read from YQL, any replies rely on that service. The nodes have references to albums and artists so that by clicking on them or pressing enter while they have the focus, it will navigate away.
This tree is built dynamically with randomized labels just to show selection, supposedly of files/folders. The Save button will list in the container below the JSON for those files/folders marked as selected.
The container for this tree has
class="yui3-fw-treeview-checkbox" set because node
selection is always active in TreeView, it just needs to be made visible through CSS styles, which
the default stylesheet contains and this className activates.