Kibana5, index pattern does not contain any of the

I have successfully set up a Kibana 4.x dashboard along with Elasticsearch 2.x, but I feel 5.x versions should be the future-proof way to go. However for some reason Kibana fails to recognize any field types when trying to visualize data, although it correctly shows types on settings and discovery views.

Prior questions on this seemed to be about geo_point types but here I'm just hoping to use basic numeric and non-analyzed string fields.

Both are running in a Docker container without any modifications to settings, FROM: kibana:5 and FROM: elasticsearch:5. I only have one index on this Poc Elasticsearch instance and it has an explicit mapping of types. I assume this configuration works for ES 5.x as well as for 2.x:

{
  "mappings": {
    "entry": {
      "_source": {
        "enabled": true
      },
      "properties": {
        "times": {
          "type": "float"
        },
        "tot_calls": {
          "type": "integer"
        },
        "time": {
          "type": "float"
        },
        "datetime": {
          "type": "date",
          "format": "YYYY-MM-dd HH:mm:ssZ"
        },
        "datetime_num": {
          "type": "long"
        },
        "env": {
          "type": "string",
          "index": "not_analyzed",
          "norms": {
            "enabled": false
          }
        },
        "ip": {
          "type": "ip"
        },
        "day": {
          "type": "integer"
        },
        "tags": {
          "type": "string",
          "index": "not_analyzed",
          "norms": {
            "enabled": false
          }
        },
        "name": {
          "type": "string",
          "index": "not_analyzed",
          "norms": {
            "enabled": false
          }
        },
        "tot_times": {
          "type": "float"
        }
      },
      "_all": {
        "enabled": false
      }
    }
  },
  "settings": {
    "number_of_shards": 3,
    "number_of_replicas": 0
  }
}

At least _source looks valid on stored documents. Any tips on how to resolve this would be welcome! The status on different views:

I had exactly the same problem. After looking everywhere on the internet, desperate, I came back to Kibana > Management > Index Patterns and clicked the orange button (refresh field list). I noticed that the columns in the "Fields" table updated, especially "aggregatable". Back to "Visualize", I celebrated with a well deserved coffee that "Field" field of "Sum" Aggregation finally accepted to discover my number typed field.

P.S. At the moment I am still struggling to have a proper graph... (I do have a table though).

Edit: Actually I was using an index pattern that was created with the "Index contains time-based events" checkbox unchecked. That is why I was experiencing this issue: https://github.com/elastic/kibana/issues/9458