title: In RStudio, scale_fill_brewer() creates grey bars as default bar graph, not a range of blues
body: <p>I'm attempting to color a bar plot with <code>scale_fill_brewer()</code> using the <code>Vocab</code> dataset from the package <code>car</code> in RStudio. </p>
  
  <pre><code>library(tidyverse)
  library(car)
  library(RColorBrewer)
  
  # An ordinal dataset
  ggplot(Vocab, aes(x = education, fill = vocabulary)) +
   geom_bar(position = "fill") +
   # Use the default brewed color palette
   scale_fill_brewer()
  </code></pre>
  
  <p>Using the an online R session via DataCamp, I am able to generate this:
  <a href="https://i.stack.imgur.com/759Bi.png" rel="nofollow noreferrer">default RColorBrewer palette is "Blues"</a></p>
  
  <p>Since the default <code>RColorBrewer</code> palette that <code>scale_fill_brewer()</code> calls is "Blues," I expect to see the above plot generated on my desktop. However, when I transfer the above code to RStudio on Windows 10, <code>ggplot2</code> generates this: <a href="https://i.stack.imgur.com/N8H1S.png" rel="nofollow noreferrer">grey bars instead of blue gradation</a></p>
  
  <p>I attempted to correct the plot by:
      # Definition of a set of blue colors from RColorBrewer package
      blues &lt;- brewer.pal(9, "Blues")</p>
  
  <pre><code># Make a color range using colorRampPalette()
  blue_range &lt;- colorRampPalette(blues)
  
  # Use blue_range to adjust the color of the bars
  ggplot(Vocab, aes(x = education, fill = vocabulary)) +
    geom_bar(position = "fill") +
    scale_fill_manual(values = blue_range(11))
  </code></pre>
  
  <p>This block of code should generate a bar plot <a href="https://i.stack.imgur.com/170hF.png" rel="nofollow noreferrer">that looks like this</a>. But, it doesn't. All of the bars are still grey. </p>
  
  <p>I don't understand why this code works on the online R session but not in my own personal RStudio session. Help?</p>