Indeed, that's broken. The problem is that callParent
and such methods are only available for methods that have been passed through Ext.define
.
You can emulate callParent
yourself by calling the parent method with the current scope and arguments. In your case, replace this.callParent()
(which is missing the arguments, by the way) with this line:
Ext.panel.Panel.prototype.onRender.apply(this, arguments);