Adding existing div as a new panel should have ui-tabs-hide class

I generate HTML to add as the contents of a new tab. When the add function is called, the new tab is created but the div is displayed on the page. In ui.tabs.js function add, if the panel doesn't exist it is created from a template and the o.hideClass is added to it. This doesn't occur if the panel already exists. This is probably incorrect and the library should be modified to add o.hideClass regardless of whether or not the panel exists.