Container to integrate an Ext4/Ext5 Container into an Ext3.4 environment with use of the Ext4/Ext5 sandbox mode. This Class uses a Ext.Panel to host the Ext4-Container.

Ext5Container.js

/**
 * @class pyriand3r.util.Ext5Container
 * This class provides a panel for an Ext5 application inside an Ext3.4 environment.
 *
 * @extends Ext.Panel
 */
pyriand3r.util.Ext5Container = Ext.extend(Ext.Panel, {
 
    /**
     * @constructor
     * Initiate panel with Ext5 container.
     */
    initComponent: function () {
        var me = this;
        this.components = {};
    
        Ext.applyIf(this, {
            containerConfig: {}
        });
    
        Ext.applyIf(this.containerConfig, {
            layout: {
                type: 'fit',
                align: 'stretch'
            }
        });
    
        Ext.apply(this.containerConfig, {
            renderTo: this.getContainerId()
        });
    
        Ext.apply(this, {
            html: '<div style="width: 100%; height: 100%;" id="' + me.getContainerId() + '"></div>',
            items: {}
        });
    
        pyriand3r.util.Ext5Container.superclass.initComponent.call(this);
 
        this.addListener('afterrender', function () {
                me.getContainer();
            }
        );
        this.addListener('resize', function (that, adjWidth, adjHeight) {
                me.getContainer().setSize(adjWidth, adjHeight);
            }
        );
        this.addListener('destroy', function () {
            me.getContainer().destroy();
        });
    },
    
    /**
     * @method
     * Return the ext5 container. Lazy
     *
     * @returns {Ext5.container.Container}
     */
    getContainer: function () {
        if (!Ext.isObject(this.components.container)) {
            this.components.container = new Ext5.container.Container(this.containerConfig);
        }
        return this.components.container;
    },
    
    /**
     * @methdo
     * Return the id of the container-div.
     *
     * @returns {string}
     */
    getContainerId: function () {
        return this.id + '_container';
    }
});