JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://cdn.sencha.com/ext/gpl/5.1.0/build/packages/ext-theme-classic/build/resources/ext-theme-classic-all.css">
<script src="http://cdn.sencha.com/ext/gpl/5.1.0/build/ext-all.js"></script>
<script src="http://cdn.sencha.com/ext/gpl/5.1.0/build/packages/ext-theme-classic/build/ext-theme-classic.js"></script>

JavaScript

Ext.onReady(function() {

        var Viewport = Ext.create("Ext.container.Viewport", {
            id: "Viewport",
            layout: "border",
            style: 'background: #fff; text-align:left;',
            frame: true,
           
            items: [
                {
                    xtype: "toolbar",
                    height: 35,
                    region: "north",
                    frame: true,
                },
                {
                    xtype: "toolbar",
                    height: 28,
                    region: 'south',
                    html: "<center>ExtJs 5.1</center>",
                },
                {
                    xtype: "panel",
                    height: 500,
                    region: "west",
                    split: true,
                    collapsible: true,
                    autoScroll: true,
                    layout: 'accordion',
                    items: [{ xtype: "panel", title: "Панель №1" }, { xtype: "panel", title: "Панель №2" }, { xtype: "panel", title: "Панель №3" }]
                },
                {
                    xtype: "panel",
                    id: "center_panel",
                    region: 'center',
                    autoScroll: true,
                    
                }

            ]
        });
    
        var win = Ext.widget("window", {
            title: "Window №1",
            width: 350, height: 250,
            maximizable: true,
            resizable: true,
            border: false,
            layout: "border",
            //constrainHeader: true,
            //constrain: true,
            x: 0, y: 0,
            renderTo: Ext.getCmp("center_panel").body,
        });
        //Ext.getCmp("viewcontainercentral").add(win);
        win.show();
    
        win.on('move', function (win, x, y) {
            if (y < 0 || x < 0) {
                win.setPosition(x < 0 ? 0 : x, y < 0 ? 0 : y);              
            }
        });
    
    
});