title: reorder is not sorting bars correctly
body: <p>I am trying to sort facet bars by a numeric value via <code>reorder()</code>, but I can't seem to get it to work. I pasted my approach below.</p>
  
  <p><a href="https://i.stack.imgur.com/toAoS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/toAoS.png" alt="enter image description here"></a></p>
  
  <pre><code>    dat &lt;- structure(list(item1 = c("word 2", "word 2", "word 2", "word 2", 
                                      "word 1", "word 1", "word 1", "word 2", "word 1", "word 1", "word 1", 
                                      "word 2", "word 2", "word 2", "word 1", "word 2", "word 1", "word 2", 
                                      "word 1", "word 1"), item2 = c("ir", "pr", "no", "mi", "wi", 
                                                                     "pr", "fe", "pa", "ti", "la", "pa", "ex",
                                                                     "cy", "se", "pe", "ti", 
                                                                     "qu", "qu", "se", "pr"), 
                            correlation = c(0.25456134079712, 0.2519936013674, 0.235943369717533, 
                                            0.227471817443391, 0.226966823585789, 0.211693332876911,
                                            0.209447353365894, 0.207110281022818, 0.19877845972944, 
                                            0.191606462402359, 0.186883665554187, 0.179251580064878, 
                                            0.17330384364747, 0.163131910906122, 0.163131910906122, 
                                            0.154238168542876, 0.153535076033027, 0.146798885015777, 
                                            0.144380422722292, 0.142845908676349)), 
                       class = c("tbl_df", "tbl", 
                                 "data.frame"), row.names = c(NA, -20L))
  
      library(tidyverse)
      ggplot(dat, aes(x = reorder(item2, -correlation), y = correlation)) +
        geom_bar(stat = "identity") +
        facet_wrap(~ item1, scales = "free") +
        theme_classic() +
        coord_flip() +
        theme(axis.title.y=element_blank())
  </code></pre>
  
  <p><strong>Update 1:</strong></p>
  
  <p>I simplified the example <code>item2</code> variable but kept two repeat values "a" and "b" that have correlations with "word 1" and "word 2". I also incorporated the suggestion to add <code>max</code> to <code>reorder()</code>.</p>
  
  <p>Each facet is sorted by its <code>correlation</code> with <code>item2</code>, but "b" in the "word 1" facet appears out of order. "b" appears in the "word 2" facet which seems to be driving the order.</p>
  
  <p><a href="https://i.stack.imgur.com/YSSzV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YSSzV.png" alt="enter image description here"></a></p>
  
  <pre><code>dat &lt;- structure(list(item1 = c("word 2", "word 2", "word 2", "word 2", 
                                  "word 1", "word 1", "word 1", "word 2", "word 1", "word 1", "word 1", 
                                  "word 2", "word 2", "word 2", "word 1", "word 2", "word 1", "word 2", 
                                  "word 1", "word 1"), item2 = c("a", "b", "c", "d", "a", 
                                                                 "f", "g", "h", "i", "j", "k", "l",
                                                                 "m", "n", "o", "p", 
                                                                 "q", "r", "s", "b"), 
                        correlation = c(0.25456134079712, 0.2519936013674, 0.235943369717533, 
                                        0.227471817443391, 0.226966823585789, 0.211693332876911,
                                        0.209447353365894, 0.207110281022818, 0.19877845972944, 
                                        0.191606462402359, 0.186883665554187, 0.179251580064878, 
                                        0.17330384364747, 0.163131910906122, 0.163131910906122, 
                                        0.154238168542876, 0.153535076033027, 0.146798885015777, 
                                        0.144380422722292, 0.142845908676349)), 
                   class = c("tbl_df", "tbl", 
                             "data.frame"), row.names = c(NA, -20L))
  
  library(tidyverse)
  ggplot(dat, aes(x = reorder(item2, correlation, max), y = correlation)) +
    geom_bar(stat = "identity") +
    facet_wrap(~ item1, scales = "free") +
    theme_classic() +
    coord_flip() +
    theme(axis.title.y=element_blank())
  </code></pre>