jQueryUI dialog won't go modal

I need a modal dialog to open ontop of an tinyMCE editor and o开发者_Go百科ther jQuerified items. I followed the jquery site but its not modal, I can still change and access the rest of the page.

$('#sureDelete').dialog({
                    modal: true,
                    buttons: {
                        "Yes": function(){
                            $('li#'+$id).remove();
                        },
                        "No":function(){
                        }
                    },
                    draggable: false
        });
<div id="dialogs">

<div id="sureDelete">Are you sure you want to delete this page?</div> </div> Also I don't have any styling added to the dialog. Can that be an issue?

You need to make sure you include the jQueryUI base css file.
I.E.:

<link rel="stylesheet" href="*jQueryUIDir*/css/*themeDir*/jquery-ui-*version*.custom.css"  type="text/css" />