title: z-index on a table row not working
body: <p>I have a table and a vertical div that suppose to be on top of all the rows but one. It has <code>position:absolute; z-index:1</code> and the row has <code>position:relative; z-index:2</code> and it doesn't work.</p>
  
  <p><a href="http://codepen.io/ilyador/pen/XJKjVw/?editors=110" rel="nofollow">http://codepen.io/ilyador/pen/XJKjVw/?editors=110</a></p>
  
  <p>The grey vertical line (<code>.marker</code>) should be under the <code>40Db</code> row (<code>.current-volume</code>), and visible over all the others like it is now.</p>