void clearCachedTouchbars() {
      if (current != null) {
        current.release();
        current = null;
      }
      if (actions != null) {
        final TBPanel tb = ourActions2Touchbar.remove(actions);
        if (tb != null) tb.release();
      }

      if (altActions != null) {
        for (ActionGroup ag : altActions.values()) {
          final TBPanel tb = ourActions2Touchbar.remove(ag);
          if (tb != null) tb.release();
        }
      }

      if (customTouchbar != null) {
        customTouchbar.release();
      }
    }
void clearCachedTouchbars()