Fix the animation of the RadWrapPanel.
As a workaround:
<telerik:RadWrapPanel >
			<i:Interaction.Behaviors>
				<ei:FluidMoveBehavior AppliesTo="Children" Duration="0:0:0.4">
					<ei:FluidMoveBehavior.EaseY>
						<CubicEase EasingMode="EaseOut"/>
					</ei:FluidMoveBehavior.EaseY>
					<ei:FluidMoveBehavior.EaseX>
						<CubicEase EasingMode="EaseOut"/>
					</ei:FluidMoveBehavior.EaseX>
				</ei:FluidMoveBehavior>
			</i:Interaction.Behaviors>
</telerik:RadWrapPanel>
Check the attached project.