/**
* Returns tree component and creates it if it's not there yet.
*
* @return tree component.
*/
private JComponent getTreeComponent() {
if (tree == null) {
CTree cmp = new CTree(collection, readingLists);
cmp.getSelectionModel().addTreeSelectionListener(itemListener);
tree = new JScrollPane(cmp);
}
return tree;
}
