From da3a6591304e50b6129e08a35fb142e71653867c Mon Sep 17 00:00:00 2001
From: nek0der <nekoder@nekoder.com>
Date: Sun, 25 Jan 2026 12:17:31 +0900
Subject: [PATCH] Fix: Prevent multiple settings windows from opening

- Check App.Windows for existing SettingsWindow before creating new one
- Use LINQ FirstOrDefault to find open settings window
- Activate existing window instead of creating duplicate
- Remove need for instance field and event handler cleanup
- Follow single source of truth pattern with App.Windows collection
---
 MainWindow.xaml.cs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/MainWindow.xaml.cs b/MainWindow.xaml.cs
index 5ef52e7..e48147e 100644
--- a/MainWindow.xaml.cs
+++ b/MainWindow.xaml.cs
@@ -1,5 +1,6 @@
 using System.Drawing;
 using System.Drawing.Drawing2D;
+using System.Linq;
 using System.Runtime.InteropServices;
 using CodexBarWin.Models;
 using CodexBarWin.Services;
@@ -234,6 +235,15 @@ private void OnFrameNavigated(object sender, Microsoft.UI.Xaml.Navigation.Naviga
 
     private void OnSettingsRequested(object? sender, EventArgs e)
     {
+        // Check if settings window is already open
+        var existingWindow = App.Windows.OfType<SettingsWindow>().FirstOrDefault();
+        if (existingWindow != null)
+        {
+            existingWindow.Activate();
+            return;
+        }
+
+        // Create and show new settings window
         var settingsWindow = new SettingsWindow();
         settingsWindow.Activate();
     }