time axis is not chronological

[jwkvam]

demo:
https://codepen.io/anon/pen/dOeWBw?editors=0010

In the example I have two traces. The second one has time points that precede the first trace. These extra time points get appended to the axis instead of being prepended like I was expecting.

I can work around this issue by first checking which trace has the earliest timestamps. I would rather not need to check for this if possible, thanks!

[etpinard]

duplicate of #1003

which will be fixed in the next release v1.21.0