title: No output from ggplot when running as a script
body: <p>Sorry to bother you with what is for sure a very simple mistake, but I still cannot figure it out by myself:</p>
  <pre><code>library(ggplot2)
  
  X = rep(c(1:6),3)
  Y = rep(c(1:6),3)
  group = rep(c(1:3), each = 6)
  
  data = data.frame(X = X, Y = Y, group = group)
  
  ggplot(data, aes(x = X, y = Y, group = group)) + geom_point() 
  </code></pre>
  <p>I do not get any output from this when I run as a script -- no figure is created. What am I doing wrong here?</p>