codice:
	<? 
...
if( get_option('page_for_posts')){
    $posts_page_id = get_option('page_for_posts');
} elseif( mfn_opts_get('blog-page')){
    $posts_page_id = mfn_opts_get('blog-page');// Blog
}
$sidebars = mfn_opts_get('sidebars');
// Category ---
if( is_category()){
    $category = get_query_var('cat');
    $category = get_category( $category );
    
    $cat_sidebar ='blog-cat-'. $category->slug;
    
    if( is_active_sidebar( $cat_sidebar )){
        
        $sidebar=$cat_sidebar;
    }          
}
// Blog --
if(! $sidebar ){
        
    $sidebar = get_post_meta( $posts_page_id,'mfn-post-sidebar',true);
    
    $sidebar = $sidebars[$sidebar];
    }
if( $_GET && key_exists('mfn-s', $_GET)) $sidebar = $_GET['mfn-s'];// demo
// sidebar 2 -
$sidebar2 = get_post_meta( $posts_page_id,'mfn-post-sidebar2',true);
if( $sidebar2 || $sidebar2 ==='0') $sidebar2 = $sidebars[$sidebar2];
if( $_GET && key_exists('mfn-s2', $_GET)) $sidebar2 = $_GET['mfn-s2'];
if( mfn_sidebar_classes()){
    echo '<div class="sidebar sidebar-1 four columns">';
        echo '<div class="widget-area clearfix '. mfn_opts_get('sidebar-lines').'">';
            if(! dynamic_sidebar( $sidebar )) mfn_nosidebar();
        echo '</div>';
    echo '</div>';
    // both sidebars
    if( mfn_sidebar_classes(true)){
        echo '<div class="sidebar sidebar-2 four columns">';
            echo '<div class="widget-area clearfix '. mfn_opts_get('sidebar-lines').'">';
                if(! dynamic_sidebar( $sidebar2 )) mfn_nosidebar();
            echo '</div>';
        echo '</div>';
    }
}
?>