title: Display all values in a Shiny selectInput box (1000+)
body: <p>I am working an a Shiny app where I want to allow the user to pick from a longer list of genes (~1800) and then have corresponding graphs for the selected gene displayed. My problem is that I cannot get Shiny to display the whole list of genes available to select from in the drop-down menu of the selectInput box, it seems that only the first 1000 or so get displayed.</p>
  
  <p>Then I found a promising solution using server-side selectize, where all the available options get displayed when the user starts typing into the select box. However, when the user is not typing, the drop-down menu still doesn´t display more than the first 1000 genes, which can suggest that there are not more options available.</p>
  
  <p>I recreated the problem with a different data set (1396 airport codes) for illustration purposes:</p>
  
  <pre><code>library(shiny)
  library(nycflights13)
  
  ui &lt;- fluidPage(
    wellPanel(
      fluidRow(
        column(12, offset = 0,
          titlePanel("Look up airports"))),
      fluidRow(
        column(3, offset = 0,
          selectizeInput(inputId = "airportCode", label = "", choices = NULL,
            options = list(placeholder = "Type airport code"))))
    )
  )
  
  server &lt;- function(input, output, session) {
    updateSelectizeInput(session, "airportCode",
      choices = as.vector(airports$faa), server = TRUE)
  }
  
  shinyApp(ui = ui, server = server)
  </code></pre>
  
  <p>When you don´t type into the select box, the last airport code displayed in the drop-down menu is only "PAM". Yet when you start typing you can get all the way down to the last one "ZYP", which I think this is rather confusing to the user. </p>
  
  <p>Best would be to have all of the values appear in the drop-down menu, if that is somehow feasible. Otherwise have none at all listed there and have them only show up when you start typing.</p>