title: Aesthetics issue using position dodge in ggplots with geom_errorbar
body: <p>I am having a problem with plotting error bars for a dataset. </p>
  
  <p>Here follows some code, i hope you can help me out, because i have researched the problem quite thoroughly, but i have not yet been able to figure out why it doesn't work. I am not a very experience programmer or R user, but i would like to think that also not a beginner. </p>
  
  <pre><code>&gt; fruit_params
  Fruits variable N     value        sd         se        ci
  Apple  January 3  319.4667 289.32861 167.043950 718.73211
  Apple  Febuary 3  373.8000 251.00398 144.917218 623.52846
  Apple    March 3  217.8000  13.03994   7.528612  32.39300
  Apple    April 3  424.6333  39.11948  22.585639  97.17816
  Apple      May 3 1160.6667  40.27820  23.254629 100.05659
  Apple     June 3 1510.3333 269.31828 155.490979 669.02368
  Orange  January 3  241.1667  65.83877  38.012030 163.55257
  Orange  Febuary 3  317.4667 204.09195 117.832541 506.99251
  Orange    March 3  224.4667  23.13144  13.354941  57.46167
  Orange    April 3  329.3333  18.11307  10.457586  44.99536
  Orange      May 3 1279.6667 129.46943  74.749210 321.61989
  Orange     June 3 1167.6667  66.16142  38.198313 164.35408
  </code></pre>
  
  <p>This is my data frame. I want to plot barplots, and add error bars according to standard error of the mean (<strong>se column</strong>).</p>
  
  <pre><code>library(ggplot2)
  ggplot(data = fruit_params, aes(x = variable, y = value, fill = Fruits)) +
  geom_bar(position = "dodge", stat="identity") +
  geom_errorbar(aes(ymin = value, ymax=value+se, width=.2, position = position_dodge(0.9)))
  </code></pre>
  
  <p>Running this script produces the following error message:</p>
  
  <blockquote>
    <p>Advarsel: Ignoring unknown aesthetics: position
    Don't know how to automatically pick scale for object of type PositionDodge/Position/ggproto. Defaulting to continuous.
    Fejl: Aesthetics must be either length 1 or the same as the data (12): ymin, ymax, width, position, x, y, fill</p>
  </blockquote>
  
  <p>If you comment out the <strong>position = position_dodge(0.9)</strong> from the aes() of the geom_errorbar, you can plot the graph, but the error bars will be offset. </p>
  
  <p>What is the problem? Thank you for your time :-)</p>