From c6e8d8484bcf61c7d7ff2b9957069e7512a74db8 Mon Sep 17 00:00:00 2001
From: Haruki Tosa <44115752+harukitosa@users.noreply.github.com>
Date: Mon, 2 Mar 2026 14:38:23 +0900
Subject: [PATCH] Fix exclusive-access crash in WindowDragHandleView hitTest
 (#736)

Add early return for non-leftMouseDown events in DraggableView.hitTest
to prevent re-entering SwiftUI view state during mouseMoved layout
passes, which caused fatal exclusive-access violations.
---
 Sources/WindowDragHandleView.swift | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Sources/WindowDragHandleView.swift b/Sources/WindowDragHandleView.swift
index d8d23f7c..15f406e9 100644
--- a/Sources/WindowDragHandleView.swift
+++ b/Sources/WindowDragHandleView.swift
@@ -359,6 +359,13 @@ struct WindowDragHandleView: NSViewRepresentable {
 
         override func hitTest(_ point: NSPoint) -> NSView? {
             let currentEvent = NSApp.currentEvent
+            // Fast bail-out: only claim hits for left-mouse-down events.
+            // For mouseMoved / mouseEntered / etc., return nil immediately
+            // to avoid re-entering SwiftUI view state during layout passes,
+            // which causes exclusive-access crashes.
+            guard currentEvent?.type == .leftMouseDown else {
+                return nil
+            }
             let shouldCapture = windowDragHandleShouldCaptureHit(
                 point,
                 in: self,