gistfile1.js

YUI().use('widget-base', 'widget-stdmod', 'base-build', function (Y) {
    var headerContent = '<a href="#" id="someButton">Click me</a>';
    
    var myWidget = Y.Base.create('my-widget', Y.Widget, [Y.WidgetStdMod], {
        _headerButton : null, // ref to btn
        
        renderUI : function () {
            this.setStdModContent(Y.WidgetStdMod.HEADER, headerContent, Y.WidgetStdMod.REPLACE);
            var header = this.getStdModNode(Y.WidgetStdMod.HEADER);
            this._headerButton = header.one('#someButton'); // Returns null
        },
        
        bindUI : function () {
            if (this._headerButton) { // Fails, it doesn't exist
                this._headerButton.on('click', function (e) {
                    e.preventDefault();
                });
            }
        },
        
        syncUI : function () {
            var header = this.getStdModNode(Y.WidgetStdMod.HEADER);
            this._headerButton = header.one('#someButton'); // Here we can get it, but bind has already come and gone
        }
    });
    
    var myInstance = new myWidget();
    myInstance.render();
});