[gtk/wip/matthiasc/popup5] GDK W32: Only use owner windows for popups

[LRN <ruslanizhb src gnome org>]

commit 88eb2da5f39cd29d02fd161ef3180821d2502af9
Author: Руслан Ижбулатов <lrn1986 gmail com>
Date:   Tue May 28 16:39:58 2019 +0000

    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

 gdk/win32/gdksurface-win32.c | 44 +++++++++++++++++---------------------------
 1 file changed, 17 insertions(+), 27 deletions(-)
---
diff --git a/gdk/win32/gdksurface-win32.c b/gdk/win32/gdksurface-win32.c
index 07fe55b35b..d2773d748e 100644
--- 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);