@Override
      void addIntervalsFrom(@NotNull IntervalTreeImpl.IntervalNode<FoldRegionImpl> otherNode) {
        FoldRegionImpl region = getRegion(this);
        FoldRegionImpl otherRegion = getRegion(otherNode);
        if (otherRegion.mySizeBeforeUpdate > region.mySizeBeforeUpdate) {
          setNode(region, null);
          removeRegionFromGroup(region);
          removeIntervalInternal(0);
          super.addIntervalsFrom(otherNode);
        }
        else {
          otherNode.setValid(false);
          ((RangeMarkerTree.RMNode<FoldRegionImpl>)otherNode).onRemoved();
        }
      }
@Override
      void addIntervalsFrom(@NotNull IntervalTreeImpl.IntervalNode<FoldRegionImpl> otherNode)