vega-lite-api: tooltip() doesn't work when color() present

I’m sorry I can’t share the notebook right now, but I’m trying to use both tooltip() and color() on a bar chart made with vega-lite-api. Here’s the relevant snippet (I think):

    vl.y().sum('Total_Stored').title('Gigabytes per Month'),
    vl.tooltip().fieldQ('Cost/mo (USD)').format('$.2f'),
    // vl.color().fieldQ("Cost/mo (USD)")

As is, the tooptip works. Uncomment the color() line and it fails.


Interestingly, replace color with size and it works.