diff --git a/frontend/assets/js/app.js b/frontend/assets/js/app.js
index 25e64e9..053c35b 100644
--- a/frontend/assets/js/app.js
+++ b/frontend/assets/js/app.js
@@ -313,6 +313,7 @@ function selectNode(id, add = false) {
 function selectShape(id) {
     selectedShapeId = id;
     selectedNodeId = null;
+    selectedNodeIds = [];
     renderNodeList();
     renderShapeList();
     renderNetwork();
@@ -691,7 +692,7 @@ function onMouseDown(e) {
 
     const shape = getShapeAt(mx, my);
     if (shape) {
-        selectedNodeId = null; selectedShapeId = shape.id;
+        selectedNodeId = null; selectedNodeIds = []; selectedShapeId = shape.id;
         dragType = 'shape'; dragTarget = shape;
         dragOffX = mx - shape.x; dragOffY = my - shape.y;
         renderNodeList(); renderShapeList();