Sub-bucket terms agg isn't ordered correctly in series chart legend

[Bargs]

Kibana version: 6.7, master, (assuming 7.x as well but haven't tested)

Elasticsearch version: 6.7, master, (assuming 7.x as well but haven't tested)

Describe the bug:

When using a terms agg as a sub-bucket the legend does not always respect the ordering in the agg config. I suspect this depends on the order of the sub-buckets returned in the ES response. Example:

[elasticmachine]

Pinging @elastic/kibana-app

[timroes]

@Bargs could you check if that's a duplicate of #17532 or #34567?

[Bargs]

I haven't dug into the code to know for a fact but #34567 sounds the same and point #2 in @lukeelmers comment here also sounds the same.

[lukeelmers]

Yep, I believe this issue is already covered between #17532 and #34567.

When we looked into #17532, we found that the subbucket ordering issue affects the legend, and also the ordering of series values within stacked bar charts. In both cases these values are derived from the order of the first subbucket.

And #34567 is more of an enhancement request to provide more/better ways to order items in the legend.

[Bargs]

Cool, I think we can close this then. Thanks @lukeelmers