function extend_tiny_mce_defaults( $config )
{
    // comma separated list of any block-level HTML tag
    $config[\'theme_advanced_blockformats\'] = \'h1,h2,h3,h4,h5,h6,p,code,address\';
    return $init;
}
add_filter( \'tiny_mce_before_init\', \'extend_tiny_mce_defaults\', 100 );