ext有关问题啊 求高手 重置不管用

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MyDesktop.GridWindow = Ext.extend(Ext.app.Module, {    id: 'grid-win',    init: function () {        this.launcher = {            text: 'Grid Window',            iconCls: 'icon-grid',            handler: this.createWindow,            scope: this        }    },    createWindow: function () {        var desktop = this.app.getDesktop();        var win = desktop.getWindow('grid-win');        var aaa = new Ext.form.FieldSet({            xtype: 'form',            id: 'form-widgets',            title: 'Form Widgets',            width: 630,            height: 700,            frame: true,            x: 50, y: 260,            bodyStyle: {                padding: '10px 20px'            },            defaults: {                anchor: '98%',                msgTarget: 'side',                allowBlank: false            },            items: [{                xtype: 'label',                text: 'Plain Label'            }, {                fieldLabel: 'TextField',                xtype: 'textfield',                emptyText: 'Enter a value',                itemCls: 'x-form-required'            }, {                fieldLabel: 'ComboBox',                xtype: 'combo',                store: ['Foo', 'Bar'],                itemCls: 'x-form-required',                resizable: true            }, {                fieldLabel: 'DateField',                itemCls: 'x-form-required',                xtype: 'datefield'            }, {                fieldLabel: 'TimeField',                itemCls: 'x-form-required',                xtype: 'timefield'            }, {                fieldLabel: 'NumberField',                emptyText: '(This field is optional)',                allowBlank: true,                xtype: 'numberfield'            }],            buttons: [{                text: '重置',                cls: 'x-icon-btn',                iconCls: 'x-icon-btn-reset',                handler: function () {                    alert(aaa.id);//                  aaa.form.reset(); //重置form  //                  aaa.getForm().getEl().dom.reset(); //重置form                      Ext.getCmp('aaa').form.reset();                }            }]        });        if (!win) {            win = desktop.createWindow({                width: 715, height: 300, plain: true, resizable: false, modal: true, layout: 'fit', xtype: 'form',                id: 'grid-win',                title: 'Grid Window',                iconCls: 'icon-grid',                items: [aaa]            });        }        win.show();    }});