Slideshow Gallery menu for editors

function admin_menu() {
    add_menu_page(__('Slideshow', $this -> plugin_name), __('Slideshow', $this -> plugin_name), 7, "gallery", array($this, 'admin_slides'), $this -> url() . '/images/icon.png');
    $this -> menus['gallery'] = add_submenu_page("gallery", __('Manage Slides', $this -> plugin_name), __('Manage Slides', $this -> plugin_name), 7, "gallery", array($this, 'admin_slides'));
    $this -> menus['gallery-settings'] = add_submenu_page("gallery", __('Configuration', $this -> plugin_name), __('Configuration', $this -> plugin_name), 7, "gallery-settings", array($this, 'admin_settings'));

    add_action('admin_head-' . $this -> menus['gallery-settings'], array($this, 'admin_head_gallery_settings'));
}