From 534aff4a6307cd289746c993aed2c2a70be8f57b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9mi=20Bernon?= <rbernon@codeweavers.com>
Date: Thu, 20 Jun 2024 23:59:52 +0200
Subject: [PATCH] server: Use a separate variable to determine the message on
 Alt release.

Based on a patch by Huw Davies.
---
 server/queue.c      | 11 +++++------
 server/user.h       |  1 +
 server/winstation.c |  1 +
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/server/queue.c b/server/queue.c
index 1a98714004c..c17446a1dd9 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -2171,17 +2171,16 @@ static int queue_keyboard_message( struct desktop *desktop, user_handle_t win, c
         if (input->kbd.flags & KEYEVENTF_KEYUP)
         {
             /* send WM_SYSKEYUP if Alt still pressed and no other key in between */
-            /* we use 0x02 as a flag to track if some other SYSKEYUP was sent already */
-            if ((desktop->keystate[VK_MENU] & 0x82) != 0x82) break;
+            if (!(desktop->keystate[VK_MENU] & 0x80) || !desktop->alt_pressed) break;
             message_code = WM_SYSKEYUP;
-            desktop->keystate[VK_MENU] &= ~0x02;
+            desktop->alt_pressed = 0;
         }
         else
         {
             /* send WM_SYSKEYDOWN for Alt except with Ctrl */
             if (desktop->keystate[VK_CONTROL] & 0x80) break;
             message_code = WM_SYSKEYDOWN;
-            desktop->keystate[VK_MENU] |= 0x02;
+            desktop->alt_pressed = 1;
         }
         break;
 
@@ -2191,7 +2190,7 @@ static int queue_keyboard_message( struct desktop *desktop, user_handle_t win, c
         if (!(input->kbd.flags & KEYEVENTF_KEYUP)) break;
         if (!(desktop->keystate[VK_MENU] & 0x80)) break;
         message_code = WM_SYSKEYUP;
-        desktop->keystate[VK_MENU] &= ~0x02;
+        desktop->alt_pressed = 0;
         break;
 
     default:
@@ -2201,7 +2200,7 @@ static int queue_keyboard_message( struct desktop *desktop, user_handle_t win, c
         /* fall through */
     case VK_F10:
         message_code = (input->kbd.flags & KEYEVENTF_KEYUP) ? WM_SYSKEYUP : WM_SYSKEYDOWN;
-        desktop->keystate[VK_MENU] &= ~0x02;
+        desktop->alt_pressed = 0;
         break;
     }
 
diff --git a/server/user.h b/server/user.h
index 7355177e13d..99491293a7c 100644
--- a/server/user.h
+++ b/server/user.h
@@ -81,6 +81,7 @@ struct desktop
     struct thread_input *foreground_input; /* thread input of foreground thread */
     unsigned int         users;            /* processes and threads using this desktop */
     unsigned char        keystate[256];    /* asynchronous key state */
+    unsigned char        alt_pressed;      /* last key press was Alt (used to determine msg on release) */
     struct key_repeat    key_repeat;       /* key auto-repeat */
     unsigned int         clip_flags;       /* last cursor clip flags */
     user_handle_t        cursor_win;       /* window that contains the cursor */
diff --git a/server/winstation.c b/server/winstation.c
index 300d899638b..63bdc3389de 100644
--- a/server/winstation.c
+++ b/server/winstation.c
@@ -294,6 +294,7 @@ static struct desktop *create_desktop( const struct unicode_str *name, unsigned
             list_init( &desktop->threads );
             desktop->clip_flags = 0;
             desktop->cursor_win = 0;
+            desktop->alt_pressed = 0;
             memset( desktop->keystate, 0, sizeof(desktop->keystate) );
             memset( &desktop->key_repeat, 0, sizeof(desktop->key_repeat) );
             list_add_tail( &winstation->desktops, &desktop->entry );