Disable Default Animation in RadTreeView
By default the RadTreeView control's items are expanded and collapsed with an animation. However, there are cases when you might want to disable these animations, e.g. when you have a large number of subitems and it takes a longer time for the animations to complete. To disable the default animations, all you have to do is to set the following attached property to the RadTreeView control:
The default duration of the expand animation is 2 seconds.