Here is a basic usage example.
HTML
<div id="trees-panel"></div>
JavaScript
var unifer = new Ext.ux.TreeUnifier();
new Ext.Panel({
title: 'Two trees unified as one',
height: 200,
width: 300,
autoScroll: true,
renderTo: Ext.get('trees-panel'),
hideBorders: true,
items: [
new Ext.tree.TreePanel({
plugins: [unifer],
useArrows:true,
dataUrl: 'tree1.json.js',
root: {
text: 'root',
nodeType: 'async'
}
}),
new Ext.tree.TreePanel({
plugins: [unifer],
dataUrl: 'tree2.json.js',
root: {
text: 'root2',
nodeType: 'async'
}
})
]
});
Result
A more complex example can be found here