devomman

if( ! function_exists( 'wp_5_6_editor_wp_block_width_fix' ) ) {
    function wp_5_6_editor_wp_block_width_fix() {
        if( version_compare( get_bloginfo( 'version' ), '5.6', '>=' ) ) {
            echo '<style>.interface-interface-skeleton__editor { max-width: 100%; }</style>';
        }
    }
}
add_action( 'admin_head', 'wp_5_6_editor_wp_block_width_fix' );