code: function (control) {
          if (!this.active) { return false; }
          if (control.type == OpenLayers.Control.TYPE_BUTTON) {
              control.trigger();
              return;
          }
          if (control.type == OpenLayers.Control.TYPE_TOGGLE) {
              if (control.active) {
                  control.deactivate();
              } else {
                  control.activate();
              }
              return;
          }
          if (this.allowDepress && control.active) {
              control.deactivate();
          } else {
              var c;
              for (var i=0, len=this.controls.length; i<len; i++) {
                  c = this.controls[i];
                  if (c != control &&
                     (c.type === OpenLayers.Control.TYPE_TOOL || c.type == null)) {
                      c.deactivate();
                  }
              }
              control.activate();
          }
      }
docs: APIMethod: activateControl
  This method is called when the user click on the icon representing a
  control in the panel.
  
  Parameters:
  control - {<OpenLayers.Control>}