function _adjustForScrollbars() {
        if ($openFilesContainer[0].scrollHeight > $openFilesContainer[0].clientHeight) {
            if (!$openFilesContainer.hasClass("vertical-scroll")) {
                $openFilesContainer.addClass("vertical-scroll");
            }
        } else {
            $openFilesContainer.removeClass("vertical-scroll");
        }
    }
@private
adds the style 'vertical-scroll' if a vertical scroll bar is present