Only first trace toggled when horizontal legend and legendPosition: true

[AlanJMac]

When the legend layout is set to the horizontal orientation and the legendPosition config variable is set to true then clicking the trace names in the legend will only toggle the visibility of the first trace.
The behaviour is as expected when the legend is vertically orientated or if its position is not editable.

The layout and config to reproduce this with 2 or more traces is as follows:

var layout = {
  legend: {
    orientation: 'h'
  }
};

var config = {
  edits: {
    legendPosition: true
  }
};

This can be seen in the following codepen: https://codepen.io/alanjmac/pen/NBNmaQ

[alexcjohnson]

Confirmed. Thanks @AlanJMac for the extremely clear bug report, and for the thorough research into when it does and does not occur!