SPLOM deselect not un-highlighting points #4588

I'm trying to get the SPLOM to deselect all data points when the background is clicked. This seems to work fine under the hood, but the visual effect is not what I expected. The selection rectangle disappears, but the data point is still highlighted.

There's a Codepen here that illustrates this:
https://codepen.io/sebastian-raubach/pen/mdJPQQG

The console output is generated when I click on the background after having selected a data point, but the point is still highlighted.

I found a pull request that seems to address the exact same issue for scattergl, but not splom:
#2492

Any ideas?