code: public int waitForWindowShown(String windowName) {
      if (getScopeServices().getConnection() == null) {
        throw new CommunicationException(
            "waiting for a window failed because Opera is not connected.");
      }
  
      return getScopeServices()
          .waitForDesktopWindowShown(windowName, OperaIntervals.WINDOW_EVENT_TIMEOUT.getMs());
    }
docs: Waits until the window is shown, and then returns the window id of the window
  
  @param windowName - window to wait for shown event on
  @return id of window