dialog overlay bug

When using the dialog plugin in jquery 1.8rc3 I get this error when I hit the dialog multiple times (like open it, esc, try opening it, etc.) sometimes it's once, sometimes its 3 times:

b("<div></div>").addClass("ui-widget-overlay") is undefined

line: 199 in custom.min.js (everything was downloaded)

This is the code:

var dialog = "<div></div>";

$(dialog).dialog({

bgiframe: true,

modal: true,

title: title,

close: function (event, ui) { $(this).remove(); if ($.isFunction(onClose)) { onClose(); } },

buttons: {

Ok: function () { $(this).dialog("close"); }

}

});