I noticed that you actually turn the feature of editing the RadTreeViewItems on every time you press F2. Please note that enabling this feature once is enough. Once enabled, you will be able to edit RadTreeViewItems by pressing F2 out of the box. This is why I suggest setting the RadTreeView.IsEditable property to True and unsubscribing from the KeyDown event of the RadTreeView.
Please give this approach a try and let us know if you need any further assistance.
Pavel R. Pavlov
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