Unable to reduce point size using dots from GADMTools

Hi guys,

I use the package GADMTools to get shape files and etc. In the package, there's a function called "dots" that allows us to put dots on a map. When I use it though, the point size is not able to be reduced, despite changing it to different integer values.

My codes is as follows:

dots(map_malaya, coord , color = "darkgreen", size = 1)

Thanks!