HOW TO GET THE PARENT VALUE ON CLICK OF CHILD VALUE IN TREE GRID

How to get the value of 'VENDOR' and 'SLA' on click of 'MONTH' or 'VALUE'

hot to get value of parent from the click of child value.

Please do give me suggestion

Here is my code....

Ext.onReady(function () {

Ext.define('Person', {

extend: 'Ext.data.Model',

fields: [

{ name: 'value', type: 'int',defaultValue :null },

{ name: 'year', type: 'string' },

{ name: 'sla', type: 'string' },

{ name: 'vendor', type: 'string' },

],

});

var store = Ext.create('Ext.data.TreeStore', {

model: 'Person',

root: {

text: 'Root',

expanded: true,

children: [

{

sla: 'Effort',

children: [

{

sla: 'Effort',

vendor:'TCS',

children: [

{

vendor:'TCS',

year:'2013',

value:'99',

leaf: true

},

{

vendor:'TCS',

year:'2014',

value:'100',

leaf: true

}

]

},

{

sla: 'Effort',

vendor:'HCL',

children: [

{

vendor:'HCL',

year:'2013',

value:'99',

leaf: true

},

{

vendor:'HCL',

year:'2014',

value:'100',

leaf: true

}

]

}

]

},

{

sla: 'Variance',

children: [

{

sla: 'Variance',

vendor:'TCS',

children: [

{

vendor:'TCS',

year:'2013',

value:'95',

leaf: true

},

{

vendor:'TCS',

year:'2014',

value:'100',

leaf: true

}

]

},

{

sla: 'Variance',

vendor:'HCL',

year:'2014',

value:'93',

leaf: true

}

]

},

]

}

});

Ext.create('Ext.tree.TreePanel', {

renderTo: Ext.getBody(),

width: 1000,

height: 400,

title: 'People',

rootVisible:false,

store: store,

columns: [

{ xtype: 'treecolumn', header: 'SLA', dataIndex: 'sla', flex: 5 },

{ header: 'VENDOR', dataIndex: 'vendor', flex: 1 },

{ header: 'MONTH', dataIndex: 'year', flex: 1 },

{ header: 'VALUE', dataIndex: 'value', flex: 1 },

]

});

});