Dojo 1.6.1 custom widget does not go into postCreate in IE9, Firefox, Chrome

http://stackoverflow.com/questions/10810486/dojo-1-6-1-custom-widget-does-not-go-into-postcreate-in-ie9-firefox-chrome

by cswing

HTML

A: <div id="a"></div>
<br/>
B: <div id="b"></div>

JavaScript

dojo.require("dijit._Widget");

dojo.declare("A", [dijit._Widget], {
    data: null,
    constructor: function() {
        this.data = 'Widget A';
    },
    postCreate: function() {
        this.inherited(arguments);
        this.domNode.innerHTML = this.data;
    }
});

dojo.declare("B", [dijit._Widget], {
    data: null,
    postMixInProperties: function() {
        this.data = 'Widget B';
    },
    postCreate: function() {
        this.inherited(arguments);
        this.domNode.innerHTML = this.data;
    }    
});

new A({}, dojo.byId("a"));
new B({}, dojo.byId("b"));