Chain-wise option list in drop down list

Suppose, I have some data structure in my data model.

There are 2 folders A & B. And 1.txt & 2.txt is in Folder A and 3.txt & 4.txt is in Folder B.

Suppose, If I select folder A from option list (Dropdown) and I have applied the changes. Then file option list should show me 1.txt & 2.txt, but actually it is showing me all the text files.

My schema looks like this:
PUT log_file_raw_database
{
"settings": {
"number_of_shards": 3,
"number_of_replicas": 2
},
"mappings": {
"log": {
"properties": {
"row_index": {
"type": "integer",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"hostname": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"timestamp": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"log_bundle": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"folder_name": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"file_name": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"log_text": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
}
}
}

Can you please show a screenshot of the folders and option list dropdowns? It would help to know what you're talking about.