JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://cdn.sencha.com/ext/gpl/4.2.0/resources/css/ext-all.css">

JavaScript

Ext.onReady(function(){
    var w1 = Ext.create('Ext.window.Window', {
        title: 'Hello1',
        height: 100,
        width: 100,
        layout: 'fit',
        html:'Hi1',
        modal: true
    });
    w1.show();
    
    var w2 = Ext.create('Ext.window.Window', {
        title: 'Hello2',
        height: 100,
        width: 100,
        layout: 'fit',
        html:'Hi2',
        modal: true
    });
    w2.show();
    Ext.WindowManager.sendToBack(w2);
    //Ext.WindowManager.bringToFront(w1);
});