Hello Benny,

Thank you for posting in our forum.

I have checked your sample project in details. What I saw is you are repositioning thousands of nodes. Reposition method is by design intended to reposition a single tree node. In order to reposition thousands of nodes you may use a nodes collection, List for example, and add all the nodes at once with AddRange method. One more point. As you would remove many nodes from the tree invoke a priory UltraTree’s BeginUpdate method. After you add all nodes to their new position invoke EndUpdate.

Attached I am sending you revised version of your sample where I have implementing above mentioned approach.

Please let me know if this is what you are looking for or if I am missing something.