private void hideContainedRegions(FoldRegion region) {
        for (int i = visible.size() - 1; i >= 0; i--) {
          if (region.getStartOffset() == visible.get(i).getStartOffset()) {
            visible.remove(i);
          }
          else {
            break;
          }
        }
      }
private void hideContainedRegions(FoldRegion region)