Tim Clem : win32u: Detect a missed WM_LBUTTONUP in the size/move loop.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 1e21e82859baf1298d610021c88adcbe2a529de5
URL:    https://gitlab.winehq.org/wine/wine/-/commit/1e21e82859baf1298d610021c88adcb...

Author: Tim Clem <tclem(a)codeweavers.com>
Date:   Fri Jun 23 13:38:46 2023 -0700

win32u: Detect a missed WM_LBUTTONUP in the size/move loop.

---

 dlls/win32u/defwnd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/dlls/win32u/defwnd.c b/dlls/win32u/defwnd.c
index e5ff1a010b9..cba5f02c02e 100644
--- a/dlls/win32u/defwnd.c
+++ b/dlls/win32u/defwnd.c
@@ -788,6 +788,17 @@ static void sys_command_size_move( HWND hwnd, WPARAM wparam )
         {
             NtUserTranslateMessage( &msg, 0 );
             NtUserDispatchMessage( &msg );
+
+            /* It's possible that the window proc that handled the dispatch consumed a
+             * WM_LBUTTONUP. Detect that and terminate the loop as if we'd gotten it. */
+            if (!(NtUserGetKeyState( VK_LBUTTON ) & 0x8000))
+            {
+                DWORD last_pos = NtUserGetThreadInfo()->message_pos;
+                pt.x = ((int)(short)LOWORD( last_pos ));
+                pt.y = ((int)(short)HIWORD( last_pos ));
+                break;
+            }
+
             continue;  /* We are not interested in other messages */
         }