ExtJS Viewport produce blank page

Question

Ext.define('rgpd.view.Viewport', {
    extend: 'Ext.container.Viewport',
    layout: 'border',
    items: [{
        region: 'north',
        html: '<h1 class="x-panel-header">Page Title</h1>',
        border: false,
        margin: '0 0 5 0'
    }, {
        region: 'west',
        collapsible: true,
        title: 'Navigation',
        width: 150
        // could use a TreePanel or AccordionLayout for navigational items
    }, {
        region: 'south',
        title: 'South Panel',
        collapsible: true,
        html: 'Information goes here',
        split: true,
        height: 100,
        minHeight: 100
    }, {
        region: 'east',
        title: 'East Panel',
        collapsible: true,
        split: true,
        width: 150
    }, {
        region: 'center',
        xtype: 'tabpanel', // TabPanel itself has no title
        activeTab: 0,      // First tab active by default
        items: {
            title: 'Default Tab',
            html: 'The first tab\'s content. Others may be added dynamically'
        }
    }]
});

here is my viewport. it's loaded in the browser i checked from network console tab, I added a console.log("test") call and it appears; but a blank page is rendered on the browser. Why ? The content of the class definition comes from ExtJS document (I use ExtJS 6.0)

i found out the problem comes from my controller but i don't know why

Ext.define('rgpd.controller.cMain', {
    extend: 'Ext.app.Controller',
    models: [
        'mExemple',
        'mCorpsMetier',
        'mUtilisateur'
    ],
    stores: [
        'sExemple',
        'sCorpsMetier',
        'sUtilisateur'
    ],
    views: [
        'Exemple.View',
        'CorpsMetier.View'
    ],
    init: function() {
        this.control({
        });
    },
    onLaunch: function() {
    },
});

Answer 1

Fiddle

Works perfectly. The question is how do you insert component in your parent view. You create instance and attach it or link component with 'xtype' in your view? Provide more code and we will see.