changing colors for addWebGLHeatmap() does not work

[silberzwiebel]

I tried to change the colors of a heatmap with the following:

addWebGLHeatmap(...., gradientTexture = "skyline", ...)

addWebGLHeatmap(...., gradientTexture = "deep-sea", ...)

However, both options don't change the color of the heatmap which stays red-green.