code: function(options) {
          OpenLayers.Control.Panel.prototype.initialize.apply(this, [options]);
          var options = {
              slideFactor: this.slideFactor,
              slideRatio: this.slideRatio
          };
          this.addControls([
              new OpenLayers.Control.Pan(OpenLayers.Control.Pan.NORTH, options),
              new OpenLayers.Control.Pan(OpenLayers.Control.Pan.SOUTH, options),
              new OpenLayers.Control.Pan(OpenLayers.Control.Pan.EAST, options),
              new OpenLayers.Control.Pan(OpenLayers.Control.Pan.WEST, options)
          ]);
      }
docs: Constructor: OpenLayers.Control.PanPanel
  Add the four directional pan buttons.
  
  Parameters:
  options - {Object} An optional object whose properties will be used
  to extend the control.