disable update while collapse and expand treegrid extjs 4 - extjs4

Question

I have treegrid extjs 4.. I use proxy read, create, update and delete
but the problem is the treegrid always send update when I click collapse and expand in treegrid..
when I delete update proxy, I got collapsing failed..
anybody have idea to disable updating while collapsing and expanding??
this is my short code
Ext.define('storeLapObjTP', {
extend: 'Ext.data.TreeStore',
//storePlanningTP = Ext.create('Ext.data.TreeStore', {
pageSize:50,
autoSync: true,
model: 'mod_planningTP',
method: 'POST',
proxy: {
type: 'ajax',
api: {
read: base_url+'project/getcomplete',
create: base_url+'project/edit/'+'create',
update: base_url+'project/edit/'+'update',
destroy: base_url+'project/edit/'+'delete'
},
reader: {
type: 'json',
}
},
sorters: [{
property: 'id',
direction: 'desc'
}],
});
Ext.define('gridTPcl', {
extend: 'Ext.tree.Panel',
id:'gridLapTP',
store: storeLapTP = new storeLapObjTP,
collapsible: false,
loadMask: true,
region: 'center',
margins: '0 0 0 0',
autoScroll: false,
useArrows: true,
rootVisible: true,
multiSelect: false,
singleExpand: false,
columns:
[
{
menuDisabled: true,
sortable: false,
xtype: 'actioncolumn',
width: 20,
items: [
{
xtype: 'treecolumn',
header: 'Project Name',
dataIndex: 'name',
width: 300,
align: 'left',
},
{
header: 'Id',
dataIndex: 'id',
hidden:true
},{
text:'Anggaran (Rp.000)',
columns : [
{
header: 'Budget',
dataIndex: 'budget',
width:80,
align: 'center',
}, {
header: 'Total',
dataIndex: 'total',
width:80,
align: 'center',
}
]
}],
selModel: {
selType: 'rowmodel'
},
title: 'Project Tree',
frame: false,
tbar: new Ext.Toolbar({
id: 'tbarlaptp',
items: [
comboYearLapTP,'-',comboYearLapTP,'-',{
id : 'reloadbuttonlaptp',
text: 'Reload',
iconCls: 'reloadButton',
disabled: true,
tooltip: 'Reload Data and Ignore Change',
handler : function(){
this.up().up().store.load();
}
}]
})
,
plugins: [],
});