title: How to use a fixed color for the stat_ellipse while having grouped data?
body: <p>I would like to set just one color for the ellipses plotted but when I provide a single color (<code>stat_ellipse(color="black")</code>) or a separate color per ellipse, to <code>stat_ellipse</code>, outside the <code>aes()</code> (<code>stat_ellipse(color=ellipses_colors)</code>), I only get a single ellipse and not an ellipse per group per panel of the grid.</p>
  
  <pre><code>d &lt;- data.frame(
  
      value1 = value_in_dimension_1,
      value2 = value_in_dimension_2,
      feature1 = dimension_1,
      feature2 = dimension_2,
      type = cluster_of_point
  )
  
  
  ggplot(d, aes(value1, value2, color=type)) +
      geom_point() +
      stat_ellipse() +
      facet_grid(feature1 ~ feature2)
  </code></pre>
  
  <p>The results, when using <code>stat_ellipse()</code>:</p>
  
  <p><a href="https://i.stack.imgur.com/qexXM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qexXM.png" alt="enter image description here"></a></p>
  
  <p>The results, when using <code>stat_ellipse(color=ellipses_colors)</code> or <code>stat_ellipse(color="black")</code>:</p>
  
  <p><a href="https://i.stack.imgur.com/2RxX0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2RxX0.png" alt="enter image description here"></a></p>