From 9d54cd3b889687d3143081e00754265eb8c04697 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 15 Sep 2021 09:41:34 +0200
Subject: [PATCH 1/2] Disable win32 handling of Alt/F10 keys.

https://stackoverflow.com/questions/9627379/how-to-disable-normal-behaviour-of-alt-key/9627980#9627980

Fixes #6592.
---
 .../Interop/UnmanagedMethods.cs               | 25 +++++++++++++++++++
 .../Avalonia.Win32/WindowImpl.AppWndProc.cs   |  6 +++++
 2 files changed, 31 insertions(+)

diff --git a/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs b/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs
index ad409810b8..6a6bcc5715 100644
--- a/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs
+++ b/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs
@@ -808,6 +808,31 @@ namespace Avalonia.Win32.Interop
             MNC_SELECT = 3
         }
 
+        public enum SysCommands
+        {
+            SC_SIZE = 0xF000,
+            SC_MOVE = 0xF010,
+            SC_MINIMIZE = 0xF020,
+            SC_MAXIMIZE = 0xF030,
+            SC_NEXTWINDOW = 0xF040,
+            SC_PREVWINDOW = 0xF050,
+            SC_CLOSE = 0xF060,
+            SC_VSCROLL = 0xF070,
+            SC_HSCROLL = 0xF080,
+            SC_MOUSEMENU = 0xF090,
+            SC_KEYMENU = 0xF100,
+            SC_ARRANGE = 0xF110,
+            SC_RESTORE = 0xF120,
+            SC_TASKLIST = 0xF130,
+            SC_SCREENSAVE = 0xF140,
+            SC_HOTKEY = 0xF150,
+            SC_DEFAULT = 0xF160,
+            SC_MONITORPOWER = 0xF170,
+            SC_CONTEXTHELP = 0xF180,
+            SC_SEPARATOR = 0xF00F,
+            SCF_ISSECURE = 0x00000001,
+        }
+
         [StructLayout(LayoutKind.Sequential)]
         public struct RGBQUAD
         {
diff --git a/src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs b/src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs
index d163b3d068..f7ed2f215f 100644
--- a/src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs
+++ b/src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs
@@ -123,6 +123,12 @@ namespace Avalonia.Win32
                         break;
                     }
 
+                case WindowsMessage.WM_SYSCOMMAND:
+                    // Disable system handling of Alt/F10 menu keys.
+                    if ((SysCommands)wParam == SysCommands.SC_KEYMENU && HighWord(ToInt32(lParam)) <= 0)
+                        return IntPtr.Zero;
+                    break;
+
                 case WindowsMessage.WM_MENUCHAR:
                     {
                         // mute the system beep

From 20e970f3359160a67644d382f54305730f52da82 Mon Sep 17 00:00:00 2001
From: 0x90d <46010672+0x90d@users.noreply.github.com>
Date: Mon, 20 Sep 2021 09:48:15 +0200
Subject: [PATCH 2/2] Update DefaultMenuInteractionHandler.cs

---
 .../Platform/DefaultMenuInteractionHandler.cs                  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs b/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs
index 209feb351c..726d2c596c 100644
--- a/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs
+++ b/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs
@@ -303,7 +303,8 @@ namespace Avalonia.Controls.Platform
                 {
                     item.Parent.SelectedItem.Close();
                     SelectItemAndAncestors(item);
-                    Open(item, false);
+                    if (item.HasSubMenu)
+                        Open(item, false);
                 }
                 else
                 {