[gtk: 3/4] GdkWin32: Generate crossing event after button release

[Luca Bacci <lbacci src gnome org>]

commit cb0c1b3f0831a6522a9473a37d6ec2d8caf9c80b
Author: Luca Bacci <luca bacci982 gmail com>
Date:   Wed Apr 6 20:01:51 2022 +0200

    GdkWin32: Generate crossing event after button release
    
    Fixes #4813

 gdk/win32/gdkevents-win32.c | 76 +++++++++++++++++++++++++--------------------
 1 file changed, 43 insertions(+), 33 deletions(-)
---
diff --git a/gdk/win32/gdkevents-win32.c b/gdk/win32/gdkevents-win32.c
index de34cd8e68..a5306a42cd 100644
--- a/gdk/win32/gdkevents-win32.c
+++ b/gdk/win32/gdkevents-win32.c
@@ -2244,6 +2244,10 @@ gdk_event_translate (MSG *msg,
        button = 5;
 
     buttonup0:
+    {
+      gboolean release_implicit_grab = FALSE;
+      GdkSurface *prev_surface = NULL;
+
       GDK_NOTE (EVENTS,
                g_print (" (%d,%d)",
                         GET_X_LPARAM (msg->lParam), GET_Y_LPARAM (msg->lParam)));
@@ -2253,41 +2257,18 @@ gdk_event_translate (MSG *msg,
       g_set_object (&window, find_window_for_mouse_event (window, msg));
 
       if (pointer_grab != NULL && pointer_grab->implicit)
-       {
-         int state = build_pointer_event_state (msg);
-
-         /* We keep the implicit grab until no buttons at all are held down */
-         if ((state & GDK_ANY_BUTTON_MASK & ~(GDK_BUTTON1_MASK << (button - 1))) == 0)
-           {
-             ReleaseCapture ();
-
-             new_window = NULL;
-             hwnd = WindowFromPoint (msg->pt);
-             if (hwnd != NULL)
-               {
-                 POINT client_pt = msg->pt;
-
-                 ScreenToClient (hwnd, &client_pt);
-                 GetClientRect (hwnd, &rect);
-                 if (PtInRect (&rect, client_pt))
-                   new_window = gdk_win32_handle_table_lookup (hwnd);
-               }
+        {
+          int state = build_pointer_event_state (msg);
 
-             synthesize_crossing_events (display,
-                                          _gdk_device_manager->system_pointer,
-                                          pointer_grab->surface, new_window,
-                                         GDK_CROSSING_UNGRAB,
-                                         &msg->pt,
-                                         0, /* TODO: Set right mask */
-                                         _gdk_win32_get_next_tick (msg->time),
-                                         FALSE);
-             g_set_object (&mouse_window, new_window);
-             mouse_window_ignored_leave = NULL;
-           }
-       }
+          /* We keep the implicit grab until no buttons at all are held down */
+          if ((state & GDK_ANY_BUTTON_MASK & ~(GDK_BUTTON1_MASK << (button - 1))) == 0)
+            {
+              release_implicit_grab = TRUE;
+              prev_surface = pointer_grab->surface;
+            }
+        }
 
-      generate_button_event (GDK_BUTTON_RELEASE, button,
-                            window, msg);
+      generate_button_event (GDK_BUTTON_RELEASE, button, window, msg);
 
       impl = GDK_WIN32_SURFACE (window);
 
@@ -2296,8 +2277,37 @@ gdk_event_translate (MSG *msg,
           impl->drag_move_resize_context.button == button)
         gdk_win32_surface_end_move_resize_drag (window);
 
+      if (release_implicit_grab)
+        {
+          ReleaseCapture ();
+
+          new_window = NULL;
+          hwnd = WindowFromPoint (msg->pt);
+          if (hwnd != NULL)
+            {
+              POINT client_pt = msg->pt;
+
+              ScreenToClient (hwnd, &client_pt);
+              GetClientRect (hwnd, &rect);
+              if (PtInRect (&rect, client_pt))
+                new_window = gdk_win32_handle_table_lookup (hwnd);
+            }
+
+          synthesize_crossing_events (display,
+                                      _gdk_device_manager->system_pointer,
+                                      prev_surface, new_window,
+                                      GDK_CROSSING_UNGRAB,
+                                      &msg->pt,
+                                      0, /* TODO: Set right mask */
+                                      _gdk_win32_get_next_tick (msg->time),
+                                     FALSE);
+          g_set_object (&mouse_window, new_window);
+          mouse_window_ignored_leave = NULL;
+        }
+
       return_val = TRUE;
       break;
+    }
 
     case WM_MOUSEMOVE:
       GDK_NOTE (EVENTS,