In area chart, colors are assigned randomly

[martinhynar]

I have an area chart that displays counts of event of 2 categories - errors and warnings. In such chart, one easily adapts to fact that same color is assigned to first category and different one to second (this usually holds quite constant). However, it happens that those same colors are interchanged and assigned to opposite categories. This happens either with page refresh (this is quite expected) but also on Kibana auto-refresh. From usability perspective, it would be helpful to keep the colors constant while Kibana refreshes data.

[rashidkpc]

Fixed in master #4429