private static @Nullable String getShortcut() {
        if (ourDoubleCtrlRegistered) {
          return IdeBundle.message("double.ctrl.or.shift.shortcut",
                                   ClientSystemInfo.isMac() ? FontUtil.thinSpace() + MacKeymapUtil.CONTROL : "Ctrl"); //NON-NLS
        }
        //keymap shortcut is added automatically
        return null;
      }
private static @Nullable String getShortcut()