uneven arrays in parcoords

[alexcjohnson]

Currently if you pass uneven arrays to parcoords, everything gets truncated to the shortest array. In #2399 I tweaked it a little bit to drop length-0 dimensions[i].values arrays, and it's probably fine to continue truncating to the shortest non-empty values array. But for correspondence with other trace types, it seems like line.color should not be able to omit points, but instead should pick a default color for latter points - black perhaps, or white if you're on a dark background?

See #2399 (comment)

[gvwilson]

Hi - this issue has been sitting for a while, so as part of our effort to tidy up our public repositories I'm going to close it. If it's still a concern, we'd be grateful if you could open a new issue (with a short reproducible example if appropriate) so that we can add it to our stack. Cheers - @gvwilson