Missing down services

Hello
In my setup I'm trying to monitor the service state (up/down) of some services,
i.e.:
// Format: Label => pid file path
$settings['services']['pidFiles'] = array(
 'nginx' => '/run/nginx.pid',
  'ssh' => '/run/sshd.pid'
);

The problem is that whenever a service stops, the corresponding row is removed from the services box.
