Thank you for contacting us.
1. Could you please try setting the Edit mode in a Dispatcher.
For 2,3 and 4: I am not sure how you traverse and select tree items. Also I don't think that LostFocus is the most appropriate event.
Could you please send me a sample project reproducing the issues and demonstrating you scenario. This way I will be able to assist you faster and more appropriately.
Thank you for your cooperation.
the Telerik team
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