tentative fix (second) for line chart

src/LineChart/RosLineChart.js

@@ -100,7 +100,7 @@ class RosLineChart extends Component {
                     if (new_data[field].length >= maxPoints) {
                         new_data[field].shift();
                     }
-                    new_data[curve.topic+field] = this.state.data[field].concat([{"y": property(field)(message)}])
+                    new_data[curve.topic+field] = this.state.data[curve.topic+field].concat([{"y": property(field)(message)}])
                     return {
                         data: new_data,
                     }