hi, I had this problem as well..drove me crazy..
finally I edit file uninstall.php at plugin and then i saw delete option at WordPress dash:
—————————
* Fired when the plugin is uninstalled.
*
* @package ReduxFramework\Uninstall
* @author Dovy Paukstys <[email protected]>
* @since 3.0.0
*/
// if uninstall.php is not called by WordPress, die
if (!defined(‘redux-framework’)) {
die;
}
$option_name = ‘wporg_option’;
delete_option($option_name);
// for site options in Multisite
delete_site_option($option_name);
// drop a custom database table
global $wpdb;
$wpdb->query(“DROP TABLE IF EXISTS {$wpdb->prefix}mytable”);