to move around when the application is moved to a screen with different DPI. */

	auto zoom_shift = old_gui_zoom - _gui_zoom;

	for (Window *w : Window::Iterate()) {

		if (automatic) {

			w->left   = (w->left   * _gui_scale) / old_scale;

			w->top    = (w->top    * _gui_scale) / old_scale;

		}

		if (w->viewport != nullptr) {

			w->viewport->zoom = Clamp(ZoomLevel(w->viewport->zoom - zoom_shift), _settings_client.gui.zoom_min, _settings_client.gui.zoom_max);

		}

	}