From 8d41e3e0800cd28dc37e371cd7a7a4488c603ccf Mon Sep 17 00:00:00 2001
From: pythongosssss <125205205+pythongosssss@users.noreply.github.com>
Date: Fri, 22 May 2026 04:06:02 -0700
Subject: [PATCH] fix: firefox can give invalid drag coordinates causing
 incorrect drop position
 (https://bugzilla.mozilla.org/show_bug.cgi?id=1773886) - change to track
 during drag events

---
 .../node/useNodeDragToCanvas.test.ts          | 86 +++++++++++++++++++
 src/composables/node/useNodeDragToCanvas.ts   | 15 +++-
 2 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/src/composables/node/useNodeDragToCanvas.test.ts b/src/composables/node/useNodeDragToCanvas.test.ts
index 2842cb817a..96ad055178 100644
--- a/src/composables/node/useNodeDragToCanvas.test.ts
+++ b/src/composables/node/useNodeDragToCanvas.test.ts
@@ -456,4 +456,90 @@ describe('useNodeDragToCanvas', () => {
       expect(dispatchPointerDown(600, 250)).not.toHaveBeenCalled()
     })
   })
+
+  describe('native drag position tracking', () => {
+    beforeEach(() => {
+      mockCanvas.canvas.getBoundingClientRect.mockReturnValue({
+        left: 0,
+        right: 500,
+        top: 0,
+        bottom: 500
+      })
+      mockConvertEventToCanvasOffset.mockReturnValue([300, 300])
+    })
+
+    // happy-dom has no DragEvent constructor; MouseEvent works since the
+    // handler only reads clientX/clientY.
+    function fireDrag(x: number, y: number) {
+      document.dispatchEvent(
+        new MouseEvent('dragover', { clientX: x, clientY: y, bubbles: true })
+      )
+    }
+
+    it('should prefer tracked drag position over dragend coordinates', () => {
+      const { startDrag, setupGlobalListeners, handleNativeDrop } =
+        useNodeDragToCanvas()
+      setupGlobalListeners()
+      startDrag(mockNodeDef, 'native')
+
+      fireDrag(250, 250)
+      // dragend supplies a bad position (the Firefox bug); the tracked one
+      // from the last drag event should win.
+      handleNativeDrop(1505, 102)
+
+      expect(mockConvertEventToCanvasOffset).toHaveBeenCalledWith({
+        clientX: 250,
+        clientY: 250
+      })
+    })
+
+    it('should ignore drag events with (0, 0)', () => {
+      const { startDrag, setupGlobalListeners, handleNativeDrop } =
+        useNodeDragToCanvas()
+      setupGlobalListeners()
+      startDrag(mockNodeDef, 'native')
+
+      fireDrag(250, 250)
+      fireDrag(0, 0)
+      handleNativeDrop(1505, 102)
+
+      expect(mockConvertEventToCanvasOffset).toHaveBeenCalledWith({
+        clientX: 250,
+        clientY: 250
+      })
+    })
+
+    it('should fall back to dragend coordinates when no drag fired', () => {
+      const { startDrag, setupGlobalListeners, handleNativeDrop } =
+        useNodeDragToCanvas()
+      setupGlobalListeners()
+      startDrag(mockNodeDef, 'native')
+
+      handleNativeDrop(250, 250)
+
+      expect(mockConvertEventToCanvasOffset).toHaveBeenCalledWith({
+        clientX: 250,
+        clientY: 250
+      })
+    })
+
+    it('should clear tracked position between drags', () => {
+      const { startDrag, setupGlobalListeners, handleNativeDrop } =
+        useNodeDragToCanvas()
+      setupGlobalListeners()
+
+      startDrag(mockNodeDef, 'native')
+      fireDrag(250, 250)
+      handleNativeDrop(1505, 102)
+
+      // Second drag - no drag events, so we should fall back to args.
+      startDrag(mockNodeDef, 'native')
+      handleNativeDrop(300, 300)
+
+      expect(mockConvertEventToCanvasOffset).toHaveBeenLastCalledWith({
+        clientX: 300,
+        clientY: 300
+      })
+    })
+  })
 })
diff --git a/src/composables/node/useNodeDragToCanvas.ts b/src/composables/node/useNodeDragToCanvas.ts
index 52227b7874..982e16cd11 100644
--- a/src/composables/node/useNodeDragToCanvas.ts
+++ b/src/composables/node/useNodeDragToCanvas.ts
@@ -10,16 +10,26 @@ const isDragging = ref(false)
 const draggedNode = shallowRef<ComfyNodeDefImpl | null>(null)
 const cursorPosition = ref({ x: 0, y: 0 })
 const dragMode = ref<DragMode>('click')
+const lastNativeDragPosition = shallowRef<{ x: number; y: number } | null>(null)
 let listenersSetup = false
 
 function updatePosition(e: PointerEvent) {
   cursorPosition.value = { x: e.clientX, y: e.clientY }
 }
 
+// Firefox dragend can report stale clientX/Y and `drag` can fire with
+// (0, 0). dragover on the target reliably reports real client coords.
+// https://bugzilla.mozilla.org/show_bug.cgi?id=1773886
+function trackNativeDragPosition(e: DragEvent) {
+  if (e.clientX === 0 && e.clientY === 0) return
+  lastNativeDragPosition.value = { x: e.clientX, y: e.clientY }
+}
+
 function cancelDrag() {
   isDragging.value = false
   draggedNode.value = null
   dragMode.value = 'click'
+  lastNativeDragPosition.value = null
 }
 
 function isOverCanvas(clientX: number, clientY: number): boolean {
@@ -81,6 +91,7 @@ function setupGlobalListeners() {
   document.addEventListener('pointerdown', blockCommitPointerDown, true)
   document.addEventListener('pointerup', endDrag, true)
   document.addEventListener('keydown', handleKeydown)
+  document.addEventListener('dragover', trackNativeDragPosition)
 }
 
 function cleanupGlobalListeners() {
@@ -91,6 +102,7 @@ function cleanupGlobalListeners() {
   document.removeEventListener('pointerdown', blockCommitPointerDown, true)
   document.removeEventListener('pointerup', endDrag, true)
   document.removeEventListener('keydown', handleKeydown)
+  document.removeEventListener('dragover', trackNativeDragPosition)
 
   if (isDragging.value && dragMode.value === 'click') {
     cancelDrag()
@@ -106,8 +118,9 @@ export function useNodeDragToCanvas() {
 
   function handleNativeDrop(clientX: number, clientY: number) {
     if (dragMode.value !== 'native') return
+    const tracked = lastNativeDragPosition.value
     try {
-      addNodeAtPosition(clientX, clientY)
+      addNodeAtPosition(tracked?.x ?? clientX, tracked?.y ?? clientY)
     } finally {
       cancelDrag()
     }