code: public void setTreeModel(final TreeItemModel treeModel) {
  		getOrCreateComponentModel().treeModel = treeModel;
  		clearItemIdMaps();
  		setSelectedRows(null);
  		setExpandedRows(null);
  		setCustomTree((TreeItemIdNode) null);
  	}
docs: Sets the tree model which provides row data.
  
  @param treeModel the tree model.