jquery ui dialog + knockoutjs

Having a problem getting the dialog to show; dialog retains 'display: none' property despite call to 'open'

HTML

<script src="http://rniemeyer.github.com/KnockMeOut/Scripts/jquery.tmpl.js"></script>
<script src="http://rniemeyer.github.com/KnockMeOut/Scripts/knockout-latest.debug.js"></script>
<link rel="stylesheet" href="http://static.jquery.com/ui/css/demo-docs-theme/ui.theme.css">
<h1 class="header" data-bind="text: label"></h1>

<div id="dialog" data-bind="dialog: {autoOpen: false, title: 'Dialog test'}">foo dialog</div>

<div>
    <button id="openbutton" data-bind="dialogcmd: {id: 'dialog'}" >Open</button>
    <button id="openbutton" data-bind="dialogcmd: {id: 'dialog', cmd: 'close'}" >Close</button>
</div>

CSS

.header {
    font-size: 16px;
    font-family: sans-serif;
    font-weight: bold;
    margin-bottom: 20px;
}

JavaScript

var jQueryWidget = function(element, valueAccessor, name, constructor) {
    var options = ko.utils.unwrapObservable(valueAccessor());
    var $element = $(element);
    var $widget = $element.data(name) || constructor($element, options);
    $element.data(name, $widget);

};

ko.bindingHandlers.dialog = {
        init: function(element, valueAccessor, allBindingsAccessor, viewModel) {
            jQueryWidget(element, valueAccessor, 'dialog', function($element, options) {
                console.log("Creating dialog on "  + $element);
                return $element.dialog(options);
            });
        }        
};
    
    
ko.bindingHandlers.dialogcmd = {
        init: function(element, valueAccessor, allBindingsAccessor, viewModel) {          
            $(element).button().click(function() {
                var options = ko.utils.unwrapObservable(valueAccessor());
                var $dialog = $('#' + options.id).data('dialog');
                var isOpen = $dialog.dialog('isOpen');
                console.log("Before command dialog is open: " + isOpen);
                $dialog.dialog(options.cmd || 'open');
                return false;
            });
        }        
};

var viewModel = {
    label: ko.observable('dialog test')
};

ko.applyBindings(viewModel);