anchor.diff:      ping.serverId = this.props.serverId;
       ping.clientId = this.props.clientId;
       return (
  -      <form className="PingBox" onSubmit={this.handleSubmit}>
  -        <input type="submit" id="button" value={this.state.buttonValue} disabled={this.state.buttonDisabled} />
  -        <input type="text" placeholder="Median" id="ping_result_lag_ms" value={this.state.resultValue} size="5" readOnly />
  -        <input type="text" placeholder="Progress" id="ping_progress" value={this.state.progressValue} size="24" readOnly />
  -        msec
  -      </form>
  +      <div>
  +        <form className="PingBox" onSubmit={this.handleSubmit}>
  +          <input type="submit" id="button" value={this.state.buttonValue} disabled={this.state.buttonDisabled} />
  +          <input type="text" placeholder="Median" id="ping_result_lag_ms" value={this.state.resultValue} size="5" readOnly />
  +          <input type="text" placeholder="Progress" id="ping_progress" value={this.state.progressValue} size="24" readOnly />
  +          msec
  +        </form>
  +      <PingResultError error={this.state.error} />
  +      </div>
       );
     }
   });
  +
  +var PingResultError = React.createClass({
  +  render: function() {
  +    var error = "";
  +    if (this.props.error) {
  +      error = "Problem in sending the result: " + this.props.error + ". Please reload and retry."
  +    }
  +    return (
  +      <div className="pingResultError">{error}</div>
  +    );
  +  }
  +});
  
positive.code:           this.setState({
              buttonValue: ping.pingButton,
              resultValue: "",
              progressValue: ""
            });
          }.bind(this),
          error: function(xhr, status, err) {
            console.error(status, err.toString());
          }
        });
      };
    },
  
negative.code:         var newState = {};
          newState[propPrefix + "Id"] = data.id;
          newState[propPrefix + "City"] = data.city;
          newState[propPrefix + "CityError"] = null;
          this.setState(newState);
          if (!data.city) { // retry until we get the city
            setTimeout(this.loadLocation, this.interval, path, propPrefix);
          }
        }.bind(this),
        error: function(xhr, status, err) {
          var errString = err.toString();
          var newState = {};
          newState[propPrefix + "CityError"] = errString;
          this.setState(newState);
          console.error(status, errString);
        }.bind(this)
      });
    },
  
    getInitialState: function() {
      return {
        serverCity: "unknown location",
        serverCityError: null,
        clientCity: "unknown location",
        clientCityError: null
      };
    },
    componentDidMount: function() {
      this.loadLocation("/locations/current", "client");
  