ext布局问题

我现在想用ext布局：整个页面分为三部分，左边树，右边分上下两块，该如何布局呢？

[code="java"]
Ext.create('Ext.Viewport', {
layout: {
type: 'border',
padding: 5
},
defaults: {
split: true
},
items: [{
region: 'west',
collapsible: true,
title: 'North',
split: true,
height: 100,
minHeight: 60,
html: 'north'
},{
region: 'center',
title: 'Starts at width'
items: [{
title: 'Central',
region: 'center',
minWidth: 80,
html: 'Central'
}, {
title: 'north',
region: 'north',
flex: 1,
minWidth: 80,
html: 'north Eastern',
split: true,
collapsible: true
}]
}]
});
[/code]