Correct bug caused by always filling with transparent fill
Correct bug caused by always filling with transparent fill

uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,vega/vega-lite