How to create a modeless dialog

hi,

I created a dialog,but it is a modal dialog,it's running in the meantime the ps can't operatting

var myWindow = new Window ("dialog", undefined,undefined, {closeButton: true, borderless: false});  
var myMessage = myWindow.add ("statictext");
myMessage.text = "Hello, world!";
myWindow.show ( );

 so ,could we  create a modeless dialog?