ExtJS form sended twice - forms

Question

I have a form with search (filtering) fields like this:
xtype: 'form',
id: 'searchPanel',
title: 'Search',
collapsible: true,
bodyPadding: 10,
height: 210,
buttonAlign: 'left',
defaults: {
width: 400,
labelWidth: 120,
allowBlank: true,
enableKeyEvents: true
},
layout: {
type: 'table',
columns: 2
},
items: [
{
xtype: 'textfield',
name: 'txtFltrSiteName',
fieldLabel: 'Site name or alias',
id: 'txtFltrSiteName'
},
{
xtype: 'textfield',
name: 'txtMonthTraffic',
fieldLabel: 'Month traffic',
id: 'txtMonthTraffic',
style: 'margin-left: 100px;'
},
{
xtype: 'combo',
id: 'ddlFltrPM',
name: 'ddlFltrPM',
fieldLabel: 'Project manager',
displayField: 'display_name',
valueField: 'user_id',
editable: false,
store: new storeOfUsers({ filters: [{ property: 'user_group_code', value: 'projectmanager', exactMatch: true }] })
},
// and many other fields below
But when i click on search button, i have two post request. One - with filter in it, second is without.
My code for send button action:
xtype: 'button',
id: 'btn_srch_set',
text: 'Searh',
margin: '10 7 0 0',
width: '',
handler: function() {
var filters = new Array();
var site_name = Ext.getCmp('txtFltrSiteName').getValue();
if(site_name.length > 0)
filters.push({dataIndex: 'site_name', type: 'string', value: site_name});
var project_name = Ext.getCmp('txtFltrProjectName').getValue();
if(project_name.length > 0)
filters.push({dataIndex: 'project_name', type: 'string', value: project_name});
var pm = Ext.getCmp('ddlFltrPM').getValue();
if(pm && pm > 0)
filters.push({dataIndex: 'project_manager_id', type: 'int', value: {'eq':pm}});
// many other fields
listOfSites.filters.removeAll();
if(filters.length > 0)
listOfSites.filters.addFilters(filters);
listOfSites.store.load();
}
P.S.
When I overwrite in search button handler function this line:
filters.push({dataIndex: 'project_manager_id', type: 'string', value: pm});
Evrything is ok and there is only one request, so problem might be here. But i'm stuck and have no idea why it works such way.
Thanks for any help,
Stanislav.
UPD*
var filters = {
ftype: 'filters',
// encode and local configuration options defined previously for easier reuse
encode: true, // json encode the filter query
local: false,
filters: [{
type: 'string',
dataIndex: 'site_name'
}, {
type: 'date',
dataIndex: 'startdate'
}, {
type: 'string',
dataIndex: 'project_name'
// more fields below

Answer 1

Try following
if(filters.length > 0)
listOfSites.filters.addFilters(filters);
else
listOfSites.store.load();
addFilters() may already call sync()