title: GGPlot: how to change the background line and sort the bars
body: <p>I am using ggplot to plot the following graph (the example attached). What I want to achieve is to:</p>
  <p>1-There are grey lines between Missing and power 1-1， power_1-1 and power_1-2 and so on, but no others (see the following graph). How can I have these lines between every bar in the background?</p>
  <p>2- How can I change these lines' color (e.g., change to light blue) and line size?</p>
  <p>3- Last, is there any way to sort my graph (through coding) based on the mean? (e.g., from -0.2231, then -0.2156, ... to 0.0592)</p>
  <pre><code>library(tidyverse)
  df &lt;- data.frame(id = c(&quot;Missing&quot;,&quot;power_1-1&quot;,&quot;power_1-2&quot;,&quot;power_1-3&quot;,&quot;power_1-4&quot;,&quot;power_1-5&quot;,&quot;power_2&quot;,&quot;power_3&quot;,&quot;power_4&quot;,&quot;power_5&quot;),
                   mean = c(-0.0823,0.0592,-0.0556,-0.1037,-0.1303,-0.1478,-0.1857,-0.2074,-0.2231,-0.2156),
                   se = c(0.0609,0.0247,0.0216,0.0206,0.0202,0.0199,0.0194,0.0193,0.0205,0.0242), stringsAsFactors = FALSE)
  
  win.graph(width = 13,height = 6)
  df %&gt;%
    rowwise() %&gt;%
    mutate(CI95 = list(c(mean + 1.96 * se, mean - 1.96 * se)),
           CI99 = list(c(mean + 2.58 * se, mean - 2.58 * se))) %&gt;%
    unnest(c(CI95, CI99)) %&gt;%
    ggplot() +
    labs(x = NULL, y = NULL) +
    geom_line(aes(x = id, y = CI99, group = id, color = id)) +
    geom_line(aes(x = id, y = CI95, group = id, color = id), size = 3) +
    geom_point(aes(x = id, y = mean, color = id), fill = &quot;white&quot;, shape = 23, size = 3) +
    geom_hline(yintercept = 0, linetype = &quot;dashed&quot;) +
    geom_vline(xintercept=1:3+0.5, colour=&quot;grey70&quot;) +
    theme_classic() +
    coord_flip() 
  </code></pre>
  <p><a href="https://i.stack.imgur.com/Cjz2S.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Cjz2S.jpg" alt="example graph is shown as the following:" /></a></p>
  <p>Also, is there any way to show a legend as the following:
  <a href="https://i.stack.imgur.com/nADRV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nADRV.png" alt="enter image description here" /></a></p>