TreePanel

Example of a basic TreePanel:

var tree = new Ext.tree.TreePanel({
   title: 'Categories'
});

var root = new Ext.tree.TreeNode({
    text: 'Categories'
});
tree.setRootNode(root);

root.appendChild(new Ext.tree.TreeNode({text: 'Widgets'}));
root.appendChild(new Ext.tree.TreeNode({text: 'Utilities'}));
root.appendChild(new Ext.tree.TreeNode({text: 'Toys'}));