code: protected void clearItemIdMaps() {
  		if (getScratchMap() != null) {
  			getScratchMap().remove(CUSTOM_IDS_TO_NODE_SCRATCH_MAP_KEY);
  			getScratchMap().remove(ALL_IDS_TO_INDEX_SCRATCH_MAP_KEY);
  			getScratchMap().remove(EXPANDED_IDS_TO_INDEX_MAPPING_SCRATCH_MAP_KEY);
  		}
  	}
docs: Clear the item id maps from, the scratch map.