GDK W32: Only use owner windows for popups

GTK4 doesn't have WS_CHILD windows anymore, so hWndParent argument
to CreateWindowEx() is always interpreted as the owner window,
not the parent window.

A window with an owner:
* is above the owner in Z-order
* is destroyed when the owner is destroyed
* is hidden when the owner is minimized
This is enforced by the OS.

GTK can only allow this for popup windows.

Desktop window must never[0] be an owner.

[0]: https://devblogs.microsoft.com/oldnewthing/20040224-00/?p=40493

diff --git a/gdk/win32/gdksurface-win32.c b/gdk/win32/gdksurface-win32.c
index 07fe55b35b99cf080c6049ebdb92b39461884c4c..d2773d748e37dca94185487f693b92f2c341623d 100644 (file)
--- a/gdk/win32/gdksurface-win32.c
+++ b/gdk/win32/gdksurface-win32.c
@@ -473,7 +473,7 @@ _gdk_win32_display_create_surface (GdkDisplay     *display,
                                    int             height)
 {
   HWND hwndNew;
-  HANDLE hparent;
+  HANDLE owner;
   ATOM klass = 0;
   DWORD dwStyle = 0, dwExStyle;
   RECT rect;
@@ -494,8 +494,6 @@ _gdk_win32_display_create_surface (GdkDisplay     *display,
             g_print ("_gdk_surface_new: %s\n", (surface_type == GDK_SURFACE_TOPLEVEL ? "TOPLEVEL" :
                                                        (surface_type == GDK_SURFACE_TEMP ? "TEMP" : "???"))));
 
-  hparent = (parent != NULL) ? GDK_SURFACE_HWND (parent) : NULL;
-
   display_win32 = GDK_WIN32_DISPLAY (display);
 
   if (parent)
@@ -524,36 +522,28 @@ _gdk_win32_display_create_surface (GdkDisplay     *display,
   impl->unscaled_height = height * impl->surface_scale;
 
   dwExStyle = 0;
+  owner = NULL;
+
+  offset_x = _gdk_offset_x;
+  offset_y = _gdk_offset_y;
+  /* MSDN: We need WS_CLIPCHILDREN and WS_CLIPSIBLINGS for GL Context Creation */
+  dwStyle = WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
 
   switch (surface_type)
     {
     case GDK_SURFACE_TOPLEVEL:
-      if (parent)
-       {
-         /* The common code warns for this case. */
-         hparent = GetDesktopWindow ();
-       }
-      /* MSDN: We need WS_CLIPCHILDREN and WS_CLIPSIBLINGS for GL Context Creation */
-      dwStyle = WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
-
-      offset_x = _gdk_offset_x;
-      offset_y = _gdk_offset_y;
-      break;
-
-    case GDK_SURFACE_POPUP:
-      dwStyle = WS_POPUP;
-      dwStyle |= WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
-      offset_x = _gdk_offset_x;
-      offset_y = _gdk_offset_y;
+      dwStyle |= WS_OVERLAPPEDWINDOW;
       break;
 
     case GDK_SURFACE_TEMP:
-      /* A temp window is not necessarily a top level window */
-      dwStyle = WS_POPUP;
-      dwStyle |= WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
       dwExStyle |= WS_EX_TOOLWINDOW | WS_EX_TOPMOST;
-      offset_x = _gdk_offset_x;
-      offset_y = _gdk_offset_y;
+      /* fall through */
+    case GDK_SURFACE_POPUP:
+      dwStyle |= WS_POPUP;
+
+      /* Only popup and temp windows are fit to use the Owner Window mechanism */
+      if (parent != NULL)
+        owner = GDK_SURFACE_HWND (parent);
       break;
 
     default:
@@ -611,7 +601,7 @@ _gdk_win32_display_create_surface (GdkDisplay     *display,
                             dwStyle,
                             window_x, window_y,
                             window_width, window_height,
-                            hparent,
+                            owner,
                             NULL,
                             _gdk_dll_hinstance,
                             surface);
@@ -646,7 +636,7 @@ _gdk_win32_display_create_surface (GdkDisplay     *display,
                           window_width, window_height,
                           surface->x - offset_x,
                           surface->y - offset_y,
-                          hparent,
+                          owner,
                           hwndNew));
 
   g_free (wtitle);