Ext.container.Container not rendering to Div

Question

HI i have a Ext mvc Application which i want to render into a div but it is rendered to Body of page.

Ext.define('ExtMVC.view.app.PortalColumn', {
    extend: 'Ext.container.Container',
    alias: 'widget.portalcolumn',
    layout: 'anchor',
    renderTo: Ext.get('ContentBox'),
    requires: ['ExtMVC.view.app.Portlet'],
    layout: 'anchor',
    defaultType: 'portlet',
    cls: 'x-portal-column',
    renderTpl: Ext.get('ContentBox'),
]
});

If i remove or comment the line extend: 'Ext.container.Container', then its coming into div but CSS and drag drop features are not applied so please suggest me how can I extend Container and render into a div