Cannot open gird desktop after close it , please help

Code:

Ext.require([
        'Ext.form.*',
        'Ext.layout.container.Column',
        'Ext.tab.Panel',
        'Ext.grid.*',
        'Ext.data.*',
        'Ext.util.*',
        'Ext.state.*'
]);


Ext.define('Writer.Person', {
     extend: 'Ext.data.Model',
     fields: [
         {name: 'id', type: 'float'},
         {name: 'name', type: 'string'},
         {name: 'price',  type: 'float'}
     ]
 });
 
var store = Ext.create('Ext.data.Store', {
        model: 'Writer.Person',
        autoLoad: true,
        autoSync: true,
        proxy: {
            type: 'ajax',
            api: {
                read: 'php/newgrid.php?mytype=list',
                create: 'php/newgrid.php?mytype=add',
                update: 'php/newgrid.php?mytype=edit',
                destroy: 'php/newgrid.php?mytype=remove'
            },
            reader: {
                type: 'json',
                successProperty: 'success',
                root: 'users',
                messageProperty: 'message'
            },
            writer: {
                type: 'json',
                writeAllFields: false,
                root: 'users'
            },
            listeners: {
                exception: function(proxy, response, operation){
                    Ext.MessageBox.show({
                        title: 'REMOTE EXCEPTION',
                        msg: operation.getError(),
                        icon: Ext.MessageBox.ERROR,
                        buttons: Ext.Msg.OK
                    });
                }
            }
        },
        listeners: {
            write: function(proxy, operation){
                if (operation.action == 'destroy') {
                    //main.child('#form').setActiveRecord(null);
                }
                Ext.Msg.alert(operation.action, 'ดำเนินการเสร็จสิ้น',onSync());
                jsonData: Ext.util.JSON.encode(dataObj);
            }
        },


});




var onAddClick = function() {
    store.add({
        name: Ext.getCmp('formname').getValue(),
        price: Ext.getCmp('formprice').getValue()
    });
    myform.hide();
};


var onDeleteClick =  function() {
                var sm = grid.getSelectionModel();
                store.remove(sm.getSelection());
};


var createColumns = function (finish, start) {
        var columns = [
            new Ext.grid.RowNumberer(),
                {header: 'name',dataIndex: 'name',flex: 1},
                {header: 'price',dataIndex: 'price',flex: 1}
        ];


        return columns.slice(start || 0, finish);
};


var onSync = function(){
        store.reload();
};


var onOpenForm = function(){
        myform.show();
};


var myform = new Ext.Window({
            id : 'xform-win-addAddress',
            title:'Add item',
            layout : 'fit',
            autoShow : false,
            closeAction: 'hide',
            width  : 300,
            height : 150,
            items : [{
                xtype : 'form',
                bodyPadding : 5,
                flex : 1,
                defaultType : 'textfield',
                items : [{
                    name : 'name',
                    fieldLabel : 'Name',
                    id : 'formname',
                    allowBlank:false
                 }, {
                    name : 'price',
                    fieldLabel : 'Price',
                    id : 'formprice',
                    xtype: 'numberfield',
                    allowBlank:false
                 }]
            }],
            buttons : [{
                 text : 'save',
                 iconCls : 'add',
                 handler: this.onAddClick
             }, {
                 text : 'Cancel',
                 iconCls : 'remove',
                 handler: function(){
                   myform.hide();
                  }


            }]
});




var grid = Ext.create('Ext.grid.Panel', { 
                    store: store,                  
                    columns: createColumns(3),
                    dockedItems: [{
                        xtype: 'toolbar', 
                        items: [{
                            iconCls: 'add',
                            text: 'เพิ่มข้อมูล',
                            scope: this,
                            handler: this.onOpenForm
                        }, {
                            iconCls: 'remove',
                            text: 'ลบข้อมูล',
                            disabled: true,
                            itemId: 'delete',
                            scope: this,
                            handler: this.onDeleteClick
                        }]
                    }],
                    listeners: {
                        'selectionchange': function(view, records) {
                            grid.down('#delete').setDisabled(!records.length);
                        }
                    }
});    
              
Ext.define('MyDesktop.test', {
    extend: 'Ext.ux.desktop.Module',
    id:'grid-test',


    init : function(){
        this.launcher = {
            text: 'TEST GRID 2',
            iconCls:'icon-grid'
        };
    },
    
    createWindow : function(){
        
        var desktop = this.app.getDesktop();
        var win = desktop.getWindow('grid-test');
        if(!win){
            win = desktop.createWindow({
            //--
                id: 'grid-test',
                title:'TESTING GRID WINDOW',
                width: 500,
                height: 300,
                iconCls: 'icon-grid',
                animCollapse:false,
                constrainHeader:true,
                items: grid
            //--
            });
        }
        return win;
    }
});