Hi, In my plugin code I have one issue before load combobox listing from json data. In console i got error. [color=red]reader.read is not a function result = reader.read(me.extractResponseData(response));[/color] I have made one model in json.js Ext.define('GoogleCategoryList', { extend: 'Ext.data.Model', fields: [{name:'ID', type:'int'}, {name:'Name', type:'string'}] }); And this is my view file code Ext.define('Shopware.apps.ProductField.view.detail.Window', { override: 'Shopware.apps.Article.view.detail.Window', createDescriptionFieldSet: function() { Ext.require('GoogleCategoryList'); var articleMain = Ext.create('Ext.data.Store', { extend: 'Ext.data.Store', model: 'GoogleCategoryList', requires: ['GoogleCategoryList'], autoLoad: true, proxy: { limitParam: undefined, startParam: undefined, paramName: undefined, pageParam: undefined, noCache:false, type: 'ajax', url: "My proxy server url for json data", reader: { type: 'json', root: 'categoryList', totalProperty: 'numFound' } } }); articleMain.load(); var me = this, fields = me.callParent(arguments); fields.add({ xtype: 'textfield', name: 'attribute[swagProductType]', fieldLabel: 'Product Type :', labelWidth: 155, margin: '0 0 15', cls: Ext.baseCSSPrefix + 'test-description-long', }); fields.add({ fieldLabel:'Google Product Category', xtype:'combo', name:'attribute[swagGoogleProductCategory]', forceSelection: true, typeAhead: true, allowBlank: false, emptyText: 'Choose Google Product Category', store: articleMain, displayField: 'Name', valueField: 'ID', id: 'swagGoogleProductCategory', }); return fields; } }); Can eny one have the solution ?