/**
* Refresh skin
*/
function sliderpro_refresh_all_skins()
{
    sliderpro_refresh_skins(array('slider', 'scrollbar'));
    echo admin_url('admin.php?page=slider_pro_skin_editor');
    die;
}
    sliderpro_refresh_skins(array('slider', 'scrollbar'));
} else {
    // the slider's table already exist which means this activation is just for updating puposes
    $slider_pro_db_version = get_option('slider_pro_version');
    //make modifications to the database if needed
    if (version_compare($slider_pro_db_version, '2.0', '<')) {
        $skins_table_name = $prefix . 'sliderpro_skins';
        // rename existing tables and create the skins table
        if ($wpdb->get_var("SHOW TABLES LIKE '{$skins_table_name}'") != $skins_table_name) {
            $wpdb->query("RENAME TABLE " . $prefix . "sp_sliders TO " . $prefix . "sliderpro_sliders");
            $wpdb->query("RENAME TABLE " . $prefix . "sp_slides TO " . $prefix . "sliderpro_slides");
            $create_skins_table = "CREATE TABLE " . $prefix . "sliderpro_skins (\n\t\t\t\t\t\t\t\t\tid mediumint(9) NOT NULL AUTO_INCREMENT,\n\t\t\t\t\t\t\t\t\ttype varchar(100) NOT NULL,\n\t\t\t\t\t\t\t\t\tpath text NOT NULL,\n\t\t\t\t\t\t\t\t\tname text NOT NULL,\n\t\t\t\t\t\t\t\t\tclass text NOT NULL,\n\t\t\t\t\t\t\t\t\tdescription text NOT NULL,\n\t\t\t\t\t\t\t\t\tauthor text NOT NULL,\n\t\t\t\t\t\t\t\t\turl text NOT NULL,\n\t\t\t\t\t\t\t\t\tcontainer_dir text NOT NULL,\n\t\t\t\t\t\t\t\t\tPRIMARY KEY (id)\n\t\t\t\t\t\t\t\t\t) DEFAULT CHARSET=utf8;";
            dbDelta($create_skins_table);
        }
        // add/update skins in the database
        sliderpro_refresh_skins(array('slider', 'scrollbar'));
        // change the charset to UTF8
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_sliders CHARACTER SET utf8");
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_slides CHARACTER SET utf8");
        // change sliders.name charset to UTF8
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_sliders CHANGE name name varchar(100) CHARACTER SET latin1");
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_sliders CHANGE name name varbinary(100)");
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_sliders CHANGE name name varchar(100) CHARACTER SET utf8 NOT NULL");
        // change slides.name charset to UTF8
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_slides CHANGE name name varchar(100) CHARACTER SET latin1");
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_slides CHANGE name name varbinary(100)");
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_slides CHANGE name name varchar(100) CHARACTER SET utf8 NOT NULL");
        // change slides.content charset to UTF8
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_slides CHANGE content content text CHARACTER SET latin1");
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_slides CHANGE content content blob");
        $wpdb->query("ALTER TABLE " . $prefix . "sliderpro_slides CHANGE content content text CHARACTER SET utf8 NOT NULL");