Color markers and a line independently

Plotly R, MATLAB, Julia, Net Plotly R
1

I’m looking to make a plot like the below.

plotly_desired
plotly_desired847×587 3.93 KB

I run into problems with keeping the color of the line separate of the markers. I can make them separate if I first draw the markers, then the line:

library(plotly)
#generating data
set.seed(1)
x <- seq(1,13,1)
y <- rbinom(13,1,0.4)
signal <- ifelse(y == 1, 'sig','noSig')

df <- data.frame(x = x,y=y,signal=signal)

#plotting markers first, then line
fig <- plot_ly()
fig <- fig %>% add_trace(data = df,x=~x,y=~y,
                         mode='markers',type='scatter',color=~signal,colors=c("black","red"))
fig <- fig %>% add_trace(x = df$x,y=df$y,
                         mode = 'lines',type='scatter',line=list(color="black"),showlegend=F)
fig

plotly_get
plotly_get845×585 28.5 KB

However, I want the markers on top of the line, so why don’t I get the desired output if I draw the line first?

fig <- plot_ly()
fig <- fig %>% add_trace(x = df$x,y=df$y,
                         mode = 'lines',type='scatter',line=list(color="black"),showlegend=F)
fig <- fig %>% add_trace(data = df,x=~x,y=~y,
                         mode='markers',type='scatter',color=~signal,colors=c("black","red"))

fig

plotly_undesired
plotly_undesired845×585 27.9 KB

I also receive the following warning:

Warning messages:
1: In RColorBrewer::brewer.pal(N, "Set2") :
  minimal value for n is 3, returning requested palette with 3 different levels

2: In RColorBrewer::brewer.pal(N, "Set2") :
  minimal value for n is 3, returning requested palette with 3 different levels

Any suggestions on how to draw a plot like the first plot, with the black line behind the colored points?