Hello Minwei,
The default behavior of the current version is to reset the position . Since there are a lot of inquiries for that issue , we are going to reconsider the way RadTreeListView behaves for its future versions.
Meanwhile the only workaround I can suggest is to try scroll in to view the desired item , after the operation, using the ScrollIntoView method of RadTreeListView.
Greetings,
Pavel Pavlov
the Telerik team
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