RadComboBox IsFilterEnabled Scroll Bar Draws Incorrectly

<telerik:RadComboBox Name="Sample" DisplayMemberPath="Text" CanAutocompleteSelectItems="True" IsFilteringEnabled="True" HorizontalAlignment="Left" IsEditable="True" OpenDropDownOnFocus="True" VerticalAlignment="Top" Width="250">

When you enter text to filter the results the scroll bar acts very strangely. As you move it down it shrinks then finally re-expands as you scroll

Included a sample app that demonstrates this

http://screencast.com/t/GJXNhxEGGy3 and screen cast to demo it

https://dl.dropboxusercontent.com/u/6295901/WpfApplication3_2015-07-27%2014-36-51Z.zip Included Sample

Created using UI for WPF Q2 2015