Following code silently ignores content passed from previous decorator (stored in $content)

    public function render($content)
    {
        $element = $this->getElement();
        $view    = $element->getView();
        if (null === $view) {
            return $content;
        }

        $jQueryParams = $this->getJQueryParams();
        $attribs     = $this->getOptions();

        $helper      = $this->getHelper();
        $id          = $element->getId() . '-container';

        return $view->$helper($id, $jQueryParams, $attribs);
    }

When used like this (http://framework.zend.com/manual/en/…)

$form->setDecorators(array(
    'FormElements',
    array('TabContainer', array(
        'id'          => 'tabContainer',
        'style'       => 'width: 600px;',
    )),
    'Form',
));

it may not matter - you simply use {{FormElements}} decorator to render sub-forms with TabPane decorator. But suppose that the master form (not sub-form) had some elements like buttons that one want to be common regardles of the choosen pane? This elements were added but are not rendered at all. I think {{ZendX_JQuery_Form_Decorator_UiWidgetContainer::render}} should look like this:

    public function render($content)
    {
        $element = $this->getElement();
        $view    = $element->getView();
        if (null === $view) {
            return $content;
        }

        $placement = $this->getPlacement();
        $separator = $this->getSeparator();
        $jQueryParams = $this->getJQueryParams();
        $attribs     = $this->getOptions();

        $helper      = $this->getHelper();
        $id          = $element->getId() . '-container';

        $tabs = $view->$helper($id, $jQueryParams, $attribs);

        switch ($placement) {
            case self::PREPEND:
                return $tabs . $separator . $content;
            case self::APPEND:
                return $content . $separator . $tabs;
        }

If developer added some elements to the form than I assume he wanted them to be rendered...