title: ggplot2: change the color of error bars w/o losing customized dodge parameters
body: <p>I would like to change the color of my error bars to different colors without changing the position of the points on my graph.</p>
  
  <p>Here is a bit of my data:</p>
  
  <pre><code>df &lt;- structure(
    list(
      yrmonth = structure(
        c(
          1483228800,
          1483228800,
          1483228800,
          1485907200,
          1485907200,
          1485907200,
          1488326400,
          1488326400,
          1488326400,
          1491004800,
          1491004800,
          1491004800
        ),
        class = c("POSIXct", "POSIXt"),
        tzone = "UTC"
      ),
      index = structure(
        c(1L, 3L, 5L, 1L, 3L, 5L, 1L, 3L, 5L, 1L, 3L, 5L),
        .Label = c("N-S", "N-S", "E-W", "E-W", "OS"),
        class = "factor"
      ),
      N = c(2, 2, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1),
      GDDLettuce = c(129, 141, 27, 150.5, 209, 87, 247.5,
                     243, 188, 223, 226.5, 170),
      sd = c(
        1.4142135623731,
        4.24264068711928,
        NA,
        4.94974746830583,
        65.0538238691624,
        NA,
        12.0208152801713,
        8.48528137423857,
        NA,
        5.65685424949238,
        0.707106781186548,
        NA
      ),
      se = c(1, 3, NA, 3.5, 46, NA, 8.5, 6, NA, 4, 0.5, NA),
      ci = c(
        12.7062047361747,
        38.1186142085241,
        NA,
        44.4717165766114,
        584.485417864036,
        NA,
        108.002740257485,
        76.2372284170481,
        NA,
        50.8248189446988,
        6.35310236808735,
        NA
      )
    ),
    .Names = c("yrmonth", "index", "N", "data", "sd", "se", "ci"),
    row.names = 31:42,
    class = "data.frame"
  )
  </code></pre>
  
  <p>I have my graph set up exactly the way I want it with error bars in the right locations:</p>
  
  <pre><code>ggplot(df, aes(x=yrmonth,y=data,colour=factor(index))) + 
    geom_line(size=1, position = position_dodge(width = -300000)) + ylim(min(df$data), max(df$data)) +
    geom_errorbar(aes(ymin=data-se, ymax=data+se), width = 1000000, size = .5, 
                  position = position_dodge(width = -300000))
  </code></pre>
  
  <p>When I add one color, the color of the bars change, but it removes all the width and dodge parameters that I put in:</p>
  
  <pre><code>ggplot(df, aes(x=yrmonth,y=data,colour=factor(index))) + 
    geom_line(size=1, position = position_dodge(width = -300000)) + ylim(min(df$data), max(df$data)) +
    geom_errorbar(aes(ymin=data-se, ymax=data+se), colour = "black", width = 1000000, size = .5, 
                  position = position_dodge(width = -300000))
  </code></pre>
  
  <p>I would like the E-W error bars to be a dark green and the N-S error bars to be a dark red. I would like the lines themselves to stay the same color. Most importantly I want the error bars to stay in there same locations. For some reason, every time I change the color the position of my error bars and lines changes.</p>