win32u: Send WM_DISPLAYCHANGE message to the desktop window.

dlls/user32/desktop.c

@@ -83,6 +83,7 @@ LRESULT WINAPI DesktopWndProc( HWND hwnd, UINT message, WPARAM wParam, LPARAM lP
     case WM_NCCREATE:
     case WM_NCCALCSIZE:
     case WM_PARENTNOTIFY:
+    case WM_DISPLAYCHANGE:
         return NtUserMessageCall( hwnd, message, wParam, lParam, 0, NtUserDesktopWindowProc, FALSE );
 
     default:

dlls/win32u/defwnd.c

@@ -2953,7 +2953,8 @@ LRESULT desktop_window_proc( HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam )
     }
     case WM_NCCALCSIZE:
         return 0;
-
+    case WM_DISPLAYCHANGE:
+        return user_driver->pDesktopWindowProc( hwnd, msg, wparam, lparam );
     default:
         if (msg >= WM_USER && hwnd == get_desktop_window())
             return user_driver->pDesktopWindowProc( hwnd, msg, wparam, lparam );

dlls/win32u/sysparams.c

@@ -2487,6 +2487,8 @@ static LONG apply_display_settings( const WCHAR *devname, const DEVMODEW *devmod
         user_driver->pGetCurrentDisplaySettings( adapter->dev.device_name, &current_mode );
         adapter_release( adapter );
 
+        send_message( NtUserGetDesktopWindow(), WM_DISPLAYCHANGE, current_mode.dmBitsPerPel,
+                      MAKELPARAM( current_mode.dmPelsWidth, current_mode.dmPelsHeight ) );
         send_message_timeout( HWND_BROADCAST, WM_DISPLAYCHANGE, current_mode.dmBitsPerPel,
                               MAKELPARAM( current_mode.dmPelsWidth, current_mode.dmPelsHeight ),
                               SMTO_ABORTIFHUNG, 2000, FALSE );