diff --git a/Drawing.js b/Drawing.js
index 5530f43..d6d08da 100644
--- a/Drawing.js
+++ b/Drawing.js
@@ -6,6 +6,8 @@ import { LEFT_SIDE, RIGHT_SIDE, BOTH_SIDES } from "athena-utils/shape/Frontline.
 const ARROW = "arrow";
 const FRONTLINE = "frontline";
 
+const ADDITIONAL_SIDE = "additionalSide"; // used for Id in BOTH_SIDES style
+
 const DEFAULT_ARROW_PARAMS = {
     splineStep: 20,
     offsetDistance: 12000,
@@ -217,7 +219,7 @@ function DrawFrontline(coordinates, polygonId) {
         },
         params.protrusion
     );
-    
+
     let polygonToDraw = frontlineGeoJSON;
 
     // Only one side
@@ -231,7 +233,7 @@ function DrawFrontline(coordinates, polygonId) {
 
         let additionalPolygonToDraw = frontlineGeoJSON.rightPoly;
 
-        drawOnMap(additionalPolygonToDraw, FRONTLINE + "-" + (polygonId+1), params.paintOptionsRight);
+        drawOnMap(additionalPolygonToDraw, FRONTLINE + "-" + (polygonId + ADDITIONAL_SIDE), params.paintOptionsRight);
         return;
     }
 
@@ -275,6 +277,7 @@ function drawOnMap(frontlineGeoJSON, id, paintOptions = {}) {
     });
 }
 
+
 function handleDelete(polygonType)
 {
     if (!currentFeature) return;
@@ -294,10 +297,10 @@ function handleDelete(polygonType)
         const frontlineLayerId = polygonType + "-" + id;
 
         if (frontlineParamsMap.get(id).style == 3){ //BOTH_SIDES
-            const frontlineLayerIdB = polygonType + "-" + (id+1);
+            const frontlineLayerIdB = polygonType + "-" + (id + ADDITIONAL_SIDE);
 
             DeleteFromMap(frontlineLayerId, id);
-            DeleteFromMap(frontlineLayerIdB, id+1);
+            DeleteFromMap(frontlineLayerIdB, id + ADDITIONAL_SIDE);
             hideArrowEditor();
             hideFrontlineEditor();
             return;
@@ -520,7 +523,7 @@ document.addEventListener('DOMContentLoaded', () => {
             if (map.getLayer(frontlineLayerId)) map.removeLayer(frontlineLayerId);
             if (map.getSource(frontlineLayerId)) map.removeSource(frontlineLayerId);
 
-            drawOnMap(polygonToDrawLeft, FRONTLINE + "-" + id+1, paintOptionsLeft);
+            drawOnMap(polygonToDrawLeft, FRONTLINE + "-" + id + ADDITIONAL_SIDE, paintOptionsLeft);
             drawOnMap(polygonToDrawRight, FRONTLINE + "-" + (id), paintOptionsRight);
             
             const allFeatures = draw.getAll().features;
@@ -530,8 +533,8 @@ document.addEventListener('DOMContentLoaded', () => {
         }
 
         const frontlineLayerId = FRONTLINE + "-" + id;
-        if (map.getLayer(frontlineLayerId+1)) map.removeLayer(frontlineLayerId+1);
-        if (map.getSource(frontlineLayerId+1)) map.removeSource(frontlineLayerId+1);
+        if (map.getLayer(frontlineLayerId + ADDITIONAL_SIDE)) map.removeLayer(frontlineLayerId + ADDITIONAL_SIDE);
+        if (map.getSource(frontlineLayerId + ADDITIONAL_SIDE)) map.removeSource(frontlineLayerId + ADDITIONAL_SIDE);
         if (map.getLayer(frontlineLayerId)) map.removeLayer(frontlineLayerId);
         if (map.getSource(frontlineLayerId)) map.removeSource(frontlineLayerId);