RadComboBox Cell And Scrolling

[Ahmad]

Hi,
In my GridViewDataColumn I set following CellTemplate:
 
<StackPanel Orientation="Horizontal">
      <telerik:RadComboBox IsEditable="True" x:Name="rcb" 
                           DisplayMemberPath="Name" 
                           Loaded="RadComboBox_Loaded" 
                           Text="{Binding State, Mode=TwoWay}" Width="100"/>

      <TextBlock Text="{Binding ElementName=rcb, Path=Text}" Margin="2 0" Width="100"/>
</StackPanel>


and the RadCombobox Items can be Following Values:
VeryBad, Bad, Good Plus, Good Neg, Good, ...

I set value of the first cell to Good
(=> RadComboBox and TextBlock Both show Good)
but when I scrolling 
the text of RadCombobox change to Good Plus
but TextBlock Shows Good.

My Solution:
https://www.mediafire.com/?2v5p21y6k8w0a7o

[Ahmad]

Any Help ???