OpenLayers.Control.DragMarker = OpenLayers.Class.create();
  OpenLayers.Control.DragMarker.prototype =
    OpenLayers.Class.inherit(OpenLayers.Control.DragFeature, {
  
      initialize: function(layer, options) {
          OpenLayers.Control.prototype.initialize.apply(this, [options]);
          this.layer = layer;
          this.handlers = {
                  drag: new OpenLayers.Handler.Drag(
                      this, OpenLayers.Util.extend({down: this.downFeature,
                                                       move: this.moveFeature,
                                                       up: this.upFeature,
                                                       out: this.cancel,
                                                       done: this.doneDragging
                                                      }, this.dragCallbacks)
                          ),
                          feature: new OpenLayers.Handler.Marker(
                              this, this.layer, OpenLayers.Util.extend({over: this.overFeature,
                                                          out: this.outFeature
                                                         }, this.featureCallbacks),
                              {geometryTypes: this.geometryTypes}
                          )
                      };
      },
     
      moveFeature: function(pixel) {
          var px = this.feature.icon.px.add(pixel.x - this.lastPixel.x, pixel.y - this.lastPixel.y);;
          this.feature.moveTo(px);
          this.lastPixel = pixel;
          this.onDrag(this.feature, pixel);
      },
  
      CLASS_NAME: "OpenLayers.Control.DragMarker"
  });