Dojo: Can I add two or more widgets to the same BorderContainer region?

http://stackoverflow.com/questions/11042631/dojo-can-i-add-two-or-more-widgets-to-the-same-bordercontainer-region

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.7.2/dijit/themes/claro/claro.css">
<style type="text/css">
    body, html, #appLayout {
     height: 100%;
     width: 100%;
    }
</style>
<div id="appLayout">
</div>

JavaScript

require(["dijit/registry", "dijit/layout/BorderContainer", "dijit/layout/ContentPane", "dijit/form/Button", "dojo/query", "dojo/dom-construct", "dijit/_Widget", "dijit/_Templated", "dojo/domReady!"], function(registry, BorderContainer,  ContentPane, Button, query, domConstruct){
        
    var appLayout = new BorderContainer({
        design: "sidebar"
    }, "appLayout");
    
        
    appLayout.addChild(new ContentPane({
        region: "top",
        content: 'top 1'
    }));
    appLayout.addChild(new ContentPane({
        region: "top",
        content: 'top 2'
    }));
    
    appLayout.addChild(new ContentPane({
        region: "left",
        content: 'left 1'
    }));
    appLayout.addChild(new ContentPane({
        region: "left",
        content: 'left 1.5'
    }));
    appLayout.addChild(new ContentPane({
        region: "left",
        content: 'left 2'
    }));
    
    appLayout.addChild(new ContentPane({
        region: "center",
        content: 'center 1'
    }));
        
    appLayout.addChild(new ContentPane({
        region: "right",
        content: 'right 1'
    }));
    appLayout.addChild(new ContentPane({
        region: "right",
        content: 'right 2'
    }));
    
    var b1 = new ContentPane({
        region: "bottom"
    });    
    appLayout.addChild(b1);

    var div1 = domConstruct.create('div', {}, b1.containerNode);
    // build more html using domConstruct, like a table etc
    var btn = new Button({ label: 'My Action 1'}, 
                     domConstruct.create('div', {}, div1));

    dojo.declare("MyFormLayout", [dijit._Widget, dijit._Templated], {
        
        //put better html layout in the template
        templateString: '<div><div dojoAttachPoint="btnNode"></div></div>',
        
        postCreate: function() {
            this.inherited(arguments);
            this.button = new Button({ label: 'My Action 2'}, this.btnNode);
        }
    });

    appLayout.addChild(new ContentPane({
        region:...