Thanks for the question and your trial of WebUI Test Studio. You should be able to record the actions of adding a treenode, whether the html or Silverlight implementation, just as a user would.
After adding the node, you can then highlight it and add a verification.
Please see 'Adding Quick Verification Steps' or 'Creating Advanced Test Verifications' topics in the Dev
edition quick start guides.
All the best,
the Telerik team
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