code: @Override
      public void hide() {
          if (displayWindow != null) {
              displayWindow.setVisible(false);
              displayWindow.removeWindowFocusListener(this);
              displayWindow = null;
          }
          if (topWindow != null) {
              topWindow.removeComponentListener(this);
              topWindow = null;
          }
          if (optionalCustomPopupCloseListener != null) {
              optionalCustomPopupCloseListener.zEventCustomPopupWasClosed(this);
              optionalCustomPopupCloseListener = null;
          }
      }
docs: hide, This hides the popup window. This removes this class from the list of window focus
  listeners for the popup window, and removes this class from the list of window movement
  listeners for the top window. This can be called internally or externally. If this is called
  multiple times, then only the first call will have an effect.