[plotterparameter] do not show first option for plotter when no selection was done

conda/js/src/components/plotterparameter/PlotterParameterEditor.jsx

@@ -172,6 +172,13 @@ const mapStateToProps = (state, ownProps) => {
 		plotters: Selectors.plotterGet(state),
 		data: params[ownProps.index] || getValidObj(),
 	};
+
+	if(!obj.data.contents.hasOwnProperty('plotter') ||
+		obj.data.contents.plotters === "")
+	{
+		obj.plotters.unshift({name: "-- select an option --"})
+	};
+
 	return obj;
 };