manual color does not work properly when there's only one factor / value option

[happyshows]

dat1 <- mtcars %>% filter(vs == 1)

dat1 %>% 
  tauchart %>% 
  tau_bar('mpg','cyl','vs') %>%
  tau_legend() %>%
  tau_tooltip() %>%
  tau_color_manual('red')

[happyshows]