docs: function(control, callbacks, options) {
          OpenLayers.Handler.prototype.initialize.apply(this, arguments);
          
          if (this.documentDrag === true) {
              var me = this;
              this._docMove = function(evt) {
                  me.mousemove({
                      xy: {x: evt.clientX, y: evt.clientY},
                      element: document
                  });
              };
              this._docUp = function(evt) {
                  me.mouseup({xy: {x: evt.clientX, y: evt.clientY}});
              };
          }
      }