fluent does not stop child processes

Hi, I am trying to use `in_multiprocess` plugin, it works fine and can start child fluentd processe, but it does not stop it when I try to stop the parent fluentd process from` fluentd-ui`
Just trying to test it by setting up one child fluentd

Here are my config files:
**Parent fluend.conf**
```

@type multiprocess

cmdline -c ./Users/sohaib.maroof/.fluentd-ui/fluentd_child1/fluent.conf --daemon ./Users/sohaib.maroof/.fluentd-ui/fluentd_child1/fluent.pid --log ./Users/sohaib.maroof/.fluentd-ui/fluentd_child1/fluent.log

```
**Child fluentd.conf**
```

@type forward
port 24224

@type stdout

@type elasticsearch_dynamic
#elasticsearch host IP/domain
hosts "es_host"
index_name fluentd-${tag_parts[1]}
buffer_chunk_limit 9MB
flush_interval 1s
#buffer_chunk_size 1MB
buffer_type memory
chunk_limit_size 9MB
num_threads 20

```