A common issue when extending AbstractTreeModel is to forget implementing a specialized getPath method. https://www.zkoss.org/wiki/ZKDeveloper'sReference/MVC/Model/TreeModel#OpenTree_Nodes
The default implementation performs a depth-first-inside the model - which can lead to a full reload.
cor3000 ( 2018-09-28 14:25:45 +0800 )edit
I can't reproduce this issue, check the zkfiddle sample. If your use case is different from mine, please provide your sample.
vincentjian ( 2015-07-29 04:30:56 +0800 )edit