winex11: Don't erase the desktop window synchronously on resizes to prevent deadlocks.

dlls/winex11.drv/winpos.c

@@ -896,7 +896,7 @@ void X11DRV_resize_desktop( unsigned int width, unsigned int height )
         SetWindowPos( hwnd, 0, virtual_screen_rect.left, virtual_screen_rect.top,
                       virtual_screen_rect.right - virtual_screen_rect.left,
                       virtual_screen_rect.bottom - virtual_screen_rect.top,
-                      SWP_NOZORDER | SWP_NOACTIVATE );
+                      SWP_NOZORDER | SWP_NOACTIVATE | SWP_DEFERERASE );
         SendMessageTimeoutW( HWND_BROADCAST, WM_DISPLAYCHANGE, screen_bpp,
                              MAKELPARAM( width, height ), SMTO_ABORTIFHUNG, 2000, NULL );
     }