Animation
By default the RadPanelBar control's items are expanded and collapsed without an animation. To enable the expand\collapse animations you can use the telerik:AnimationManager.IsAnimationEnabled attached property. To customize the animation you could use the PanelBarExpandCollapseAnimation object.
Enable Animation in RadPanelBar
The animation is enabled by setting the telerik:AnimationManager.IsAnimationEnabled property to True.
Example 1: Enable expand\collapse animation
Change Animation Direction
The animation direction is controlled by the Direction property of the PanelBarExpandCollapseAnimation class and it is either In or Out.
Example 2: Set expand\collapse directions
Change Animation Speed
The speed of the expand\collapse is also customizable via the AnimationManager.AnimationSelector attached property.