On the Windows platform, there is a white space at the bottom of the full screen window

[wangchengcheng1992]

window_manager_plugin.cpp

std::optional<LRESULT> WindowManagerPlugin::HandleWindowProc(HWND hWnd,
                                                             UINT message,
                                                             WPARAM wParam,
                                                             LPARAM lParam) {
  std::optional<LRESULT> result = std::nullopt;

  if (message == WM_NCCALCSIZE) {
    // This must always be first or else the one of other two ifs will execute
    //  when window is in full screen and we don't want that
    if (wParam && window_manager->IsFullScreen()) {
      NCCALCSIZE_PARAMS* sz = reinterpret_cast<NCCALCSIZE_PARAMS*>(lParam);
      sz->rgrc[0].bottom -= 3;
      return 0;
    }
   
   ...
   ...
}

sz->rgrc[0].bottom -= 3;

Can you tell me why the bottom margin of 3px should be reserved?

Thanks