(Check this fiddle for complete sample : https://fiddle.sencha.com/#fiddle/fkb)

Assume


we have these "base" and "child" classes : Ext.define('base', { extend: 'Ext.data.Model', idProperty: 'Id', }); Ext.define('child', { extend: 'base', fields:[ 'Id','Title'], });the following "getField" method returns null : var x = new child(); console.warn(x.self.fieldsMap);//it has not Id !!! console.warn(x.getField('Id'));but if I don't use inheritance it would be ok! Also If I don't define 'Id' field in child class, it would be ok too (check 'child2' class in provided sample)It makes problem wherever this "getField" method called (like in TreePicker).