For the time delay you can use a Thread.Sleep method like so:
void PreparedItem_DragOver(object sender, DragEventArgs e)
var currentItemUndeMouse = sender as RadTreeViewItem;
if (currentItemUndeMouse != null && !currentItemUndeMouse.IsSelected)
currentItemUndeMouse.IsSelected = true;
currentItemUndeMouse.IsExpanded = true;
e.Handled = true;
As for the second, ScrollViewer problem, you can try to use the mouse events and to calculate the mouse position and to check whether the ScrollViewer can scroll down.
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!