The reported behavior with the border of the previously selected item is a known issue in RadTreeView. You can find it logged in our feedback portal
where you can track its status and vote. If you follow the feedback item you will be notified by email as soon as there is any progress on the issue.
To work this around you can subscribe for the SelectionChanged event of RadTreeView and inside its handler focus the actual selected item. Here is an example in code:
sender, Telerik.Windows.Controls.SelectionChangedEventArgs e)
(e.AddedItems.Count > 0)
var selectedItem = e.AddedItems
As for the behavior in your project, I cannot be sure what is causing it without your implementation. Can you please provide me with a sample project with your code and the modified styles? However, the forum doesn't allow attaching .zip files, so you can open new Support Ticket and refer this forum or describe the issue again.
Thank you for any help you can provide.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.