title: R Shiny: center an absolutePanel
body: <p>How do I centre an absolutePanel in Shiny?  I've tried setting left = 50% and it centres the left side of the panel.</p>
  
  <pre><code>absolutePanel(id = "myId", class = "myClass", fixed = TRUE
                      ,draggable = TRUE, top = 10, left = "50%", right = "auto", bottom = "auto"
                      ,width = 100, height = "auto"
  </code></pre>