title: Leaflet Marker not static on position
body: <p>I have notice that my leaflet markers are "not staying put" on a given lat/lon. When I zoom in on the map, the marker moves to adjust and take the correct position. When I zoom out, it goes to a different position. It'snot static on the position. How can I fix this ?  </p>
  
  <p>There is nothing special about my marker. below is how I built it</p>
  
  <pre><code>var LeafIcon = L.Icon.extend({
      options: {
          iconSize:     [12, 15],
          shadowSize:   [30, 40],
          iconAnchor:   [11, 70],
          shadowAnchor: [2, 42],
          popupAnchor:  [-3, -40]
      }
  });
  
  var map_icon = new LeafIcon({iconUrl: 'icon_marker.png'});
  var marker;
  
  marker = L.marker([my_lat, my_lon], {icon: map_icon});
      marker.addTo(map);
      marker.bindPopup("My markers' popup");
  </code></pre>