title: downloadHandler() problems: MacOS fine but no result with Windows
body: <p>I am working with R and shiny on my MacBook. The application works fine. Part of the application is the download of results. For this I have included a downloadHandler(). This works on my Mac fine, but when I copy the application on the Windows computer of a friend - nothing happens. The file dialog opens. You can select a filename - but no file is stored. I am using the internal browser of Rstudio for this. Both on Windows and MacOS.</p>
  
  <p>Does anyone has an idea?</p>
  
  <p>I copy the downloadHandler here:</p>
  
  <pre><code>output$result.download &lt;- downloadHandler(
    filename = function() { 
      paste('result-', Sys.Date(), '.csv', sep='') 
    },
    content = function(file) {
      write.table(result, file, sep=';', dec=',', na='', row.names=F)
    }
  )
  </code></pre>