Override Pagingtoolbar and add combbox item.

Hello, i have some problems with my function on overrided pagingtoolbar i just want to know why or how can i make this work :

Ext.define('aw.grid.PagingToolbar', {

extend: 'Ext.toolbar.Paging',

alias: 'widget.custompaging',

displayInfo: true,

items: [

{

xtype: 'combobox',

store: ['5', '10', '15', '20'],

width: 50,

queryMode: 'local',

allowBlank: false,

editable: false,

triggerAction: 'all',

maskRe: /[0-9]/,

listeners: {

init: function (paging) {

debugger;

var me = this;

paging.on('afterrender', me.onInitView, me);

},

onInitView: function (paging) {

var me = this;

me.setValue(paging.store.pageSize);

for (var i = 0; i < paging.items.length; i++) {

if (paging.items.items[i].xtype == 'tbfill') {

paging.remove(paging.items.items[i]);

paging.add(i, me);

}

}

me.on('select', me.onPageSizeChanged, paging);

me.on('specialkey', function (combo, e) {

if (13 === e.getKey()) {

me.onPageSizeChanged.call(paging, me);

}

});

},

onPageSizeChanged: function (combo) {

var me = this;

me.store.pageSize = parseInt(combo.getRawValue(), 10);

me.doRefresh();

}

}

},

{

xtype: 'button',

text: 'x - Rows selected'

}

]

});

The problem i have is that my listeners are not working ...and i dont know how to make this work...i dont know if its okey like this ..

Override Pagingtoolbar and add combbox item.