您可以尝试以下操作：

/**
 * Only allow shortcodes for a widget with a given title.
 *
 * @see http://wordpress.stackexchange.com/a/160246/26350
 */

function wpse_widget_shortcode( $text, $instance )
{
        // Only allow shortcodes for the widget with the following title:
        $title = \'Some Title\'; 

        remove_filter( current_filter(), __FUNCTION__ );

        if( isset( $instance[\'title\'] ) 
            && mb_strtolower( $title ) === $instance[\'title\'] 
        )
            $text = do_shortcode( $text );

        return $text;
}

add_filter( \'widget_text\', \'wpse_widget_shortcode\', 99, 2 );