From b01eea9eb4dd309ca999366a969b3144b0b6ea17 Mon Sep 17 00:00:00 2001
From: Mark Tolmacs <mark@lazycat.hu>
Date: Fri, 5 Sep 2025 16:03:24 +0200
Subject: [PATCH] fix: Overlap behavior

---
 packages/element/src/binding.ts             | 49 +++++++--------------
 packages/element/src/linearElementEditor.ts | 22 ++++++++-
 2 files changed, 36 insertions(+), 35 deletions(-)

diff --git a/packages/element/src/binding.ts b/packages/element/src/binding.ts
index 4f48c8a54..2d1728202 100644
--- a/packages/element/src/binding.ts
+++ b/packages/element/src/binding.ts
@@ -3,6 +3,7 @@ import {
   arrayToMap,
   invariant,
   isAlwaysInsideBinding,
+  isTransparent,
 } from "@excalidraw/common";
 
 import {
@@ -303,49 +304,31 @@ const bindingStrategyForNewSimpleArrowEndpointDragging = (
     }
 
     // Check and handle nested shapes
-    if (arrow.startBinding) {
+    if (hit && arrow.startBinding) {
       const otherElement = elementsMap.get(
         arrow.startBinding.elementId,
       ) as ExcalidrawBindableElement;
-      invariant(otherElement, "Other element must be in the elements map");
-      const startFocusElements = getAllHoveredElementAtPoint(
-        getGlobalFixedPointForBindableElement(
-          arrow.startBinding.fixedPoint,
-          otherElement,
-          elementsMap,
-        ),
-        elements,
-        elementsMap,
-      );
-      const startHoverElements = getAllHoveredElementAtPoint(
-        LinearElementEditor.getPointAtIndexGlobalCoordinates(
-          arrow,
-          0,
-          elementsMap,
-        ),
-        elements,
-        elementsMap,
-      );
 
-      if (
-        hit &&
-        otherElement.id !== hit.id &&
-        (startHoverElements.find((el) => el.id === hit.id) ||
-          startFocusElements.find((el) => el.id === hit.id))
-      ) {
+      invariant(otherElement, "Other element must be in the elements map");
+
+      const allHits = getAllHoveredElementAtPoint(point, elements, elementsMap);
+
+      if (allHits.find((el) => el.id === otherElement.id)) {
+        const otherIsTransparent = isTransparent(otherElement.backgroundColor);
+
         return {
           start: isMultiPoint
             ? { mode: undefined }
             : {
-                mode: "orbit",
+                mode: "inside",
                 element: otherElement,
-                focusPoint: snapToCenter(
-                  otherElement,
-                  elementsMap,
-                  origin ?? pointFrom<GlobalPoint>(arrow.x, arrow.y),
-                ),
+                focusPoint: origin ?? pointFrom<GlobalPoint>(arrow.x, arrow.y),
               },
-          end: { mode: "inside", element: hit, focusPoint: point },
+          end: {
+            mode: "inside",
+            element: otherIsTransparent ? hit : otherElement,
+            focusPoint: point,
+          },
         };
       }
     }
diff --git a/packages/element/src/linearElementEditor.ts b/packages/element/src/linearElementEditor.ts
index 5e742d056..913d66e5e 100644
--- a/packages/element/src/linearElementEditor.ts
+++ b/packages/element/src/linearElementEditor.ts
@@ -117,6 +117,7 @@ type PointMoveOtherUpdates = {
   startBinding?: FixedPointBinding | null;
   endBinding?: FixedPointBinding | null;
   moveMidPointsWithElement?: boolean | null;
+  suggestedBinding?: AppState["suggestedBinding"] | null;
 };
 
 export class LinearElementEditor {
@@ -484,6 +485,7 @@ export class LinearElementEditor {
     }
 
     // Apply the point movement if needed
+    let suggestedBinding: AppState["suggestedBinding"] = null;
     if (deltaX || deltaY) {
       const { positions, updates } = pointDraggingUpdates(
         selectedPointsIndices,
@@ -497,6 +499,13 @@ export class LinearElementEditor {
 
       LinearElementEditor.movePoints(element, app.scene, positions, updates);
 
+      // Set the suggested binding from the updates if available
+      if (isBindingElement(element, false)) {
+        if (isBindingEnabled(app.state) && (startIsSelected || endIsSelected)) {
+          suggestedBinding = updates?.suggestedBinding ?? null;
+        }
+      }
+
       // Move the arrow over the bindable object in terms of z-index
       if (isBindingElement(element) && startIsSelected !== endIsSelected) {
         moveArrowAboveBindable(
@@ -522,7 +531,6 @@ export class LinearElementEditor {
     }
 
     // Suggest bindings for first and last point if selected
-    let suggestedBinding: AppState["suggestedBinding"] = null;
     if (isBindingElement(element, false)) {
       if (isBindingEnabled(app.state) && (startIsSelected || endIsSelected)) {
         suggestedBinding = maybeSuggestBindingsForBindingElementAtCoords(
@@ -2086,7 +2094,9 @@ const pointDraggingUpdates = (
   );
 
   // Generate the next bindings for the arrow
-  const updates: PointMoveOtherUpdates = {};
+  const updates: PointMoveOtherUpdates = {
+    suggestedBinding: null,
+  };
   if (start.mode === null) {
     updates.startBinding = null;
   } else if (start.mode) {
@@ -2101,6 +2111,10 @@ const pointDraggingUpdates = (
         start.focusPoint,
       ),
     };
+
+    if (startIsDragged) {
+      updates.suggestedBinding = start.element;
+    }
   }
   if (end.mode === null) {
     updates.endBinding = null;
@@ -2116,6 +2130,10 @@ const pointDraggingUpdates = (
         end.focusPoint,
       ),
     };
+
+    if (endIsDragged) {
+      updates.suggestedBinding = end.element;
+    }
   }
 
   // Simulate the updated arrow for the bind point calculation