Negative Data By Itself Looks Good!

Putting a series with all negative values on the chart works as you'd expect, including with a group-by, which is really nice!

Combined negative and positive series has a scale issue

If you put a positive and a negative series together, the chart doesn't scale the positive part of the y axis correctly — there's some room for play there, so you get some of the data, but not all of it.

Especially if the values are the same, but inverted

And if the negative and positive series have identical but inverse values, the scale breaks entirely, displaying no data

(would expect: y axis scales to max value in both positive and negative directions regardless of the data it is fed)

Same issue for Bar charts

Again if the negative and positive series have identical but inverse values, the scale breaks entirely, displaying no data

(would expect: y axis scales to max value in both positive and negative directions regardless of the data it is fed)

When values are mixed negative and positive in the same series

Line chart seems to render them correctly? (Not totally sure the axis range is correct on negative side...)

But Area re-bases on lowest negative value instead of zero

Expected result here, I believe, is that in the same series the negative portion of data will re-base to zero (i.e. their fill flows up to zero), and the positive portions do the same (i.e. they flow down to zero)

Bar does this correctly, it appears

Negative values start from zero and go down, positive values start from zero and go up — even when the data is mixed postiive/negative over time in the same series!