title: Layer order changing when turning layer on/off
body: <p>I have two geoJson layers being loaded - both layers are the same data for testing purposes, but being drawn from two different json files. When I turn the layers on and off in the layer controller, the draw order of the layers change.</p>
  
  <p>Any ideas why this is happening?</p>
  
  <p>I have put my code into a JSFiddle: <a href="http://jsfiddle.net/lprashad/ph5y9/10/">http://jsfiddle.net/lprashad/ph5y9/10/</a> and the JS is below:</p>
  
  <pre><code>//styling for watersheds_copy
  var Orange = {
      "color": "#ff7800",
          "weight": 5,
          "opacity": 0.65
  };
  
  var Water_Orange = L.geoJson(watersheds_copy, {
      style: Orange
  });
  
  Water_Orange.addData(watersheds_copy);
  
  //these are blue
  var Water_blue = L.geoJson(watersheds, {});
  Water_blue.addData(watersheds);
  
  //This sets the inital order - last in layer list being on top. Except minimal   - tile layer is always on bottom
  var map = L.map('map', {
      center: [41.609, -74.028],
      zoom: 8,
      layers: [minimal, Water_Orange, Water_blue]
  });
  
  var baseLayers = {
      "Minimal": minimal,
          "Night View": midnight
  };
  
  //This controls the order in the layer switcher. This does not change draw order
  var overlays = {
      "Water_Orange": Water_Orange,
          "Water_blue": Water_blue
  };
  L.control.layers(baseLayers, overlays).addTo(map);
  </code></pre>
  
  <p>LP</p>