Commented Unassigned: CheckComboBox loses values when scrolled out of view [21917]

I am using a CheckComboBox within a ListView/GridView column, defined as follows...
```
<GridViewColumn Header="Surcharges">
<GridViewColumn.CellTemplate>
<DataTemplate>
<et:CheckComboBox Delimiter=" " DisplayMemberPath="PalletNetworkSurchargeCode" ItemsSource="{Binding Path=SurchargeOptions}" MinWidth="100" SelectedValue="{Binding Path=Surcharges}" ValueMemberPath="PalletNetworkSurchargeCode" Width="100" />
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
```

Within the View Model, SurchargeOptions is a List<PalletNetworkSurcharge>, PalletNetworkSurcharge.PalletNetworkSurchargeCode is a String, and SurchargeOptions is also a String.

If the user scrolls the list (quickly), or resizes the form in such a way that one or more items in the list is no longer visible, when that item is made visible again (either by more scrolling or more resizing) any items selected in the CheckComboBox are no longer selected and the clearing of the selected items is also reflected in the bound "SelectedValue".

Can you please help. Am I missing something within the Xaml or is there a problem with the control?

Thanks.

Martin.
Comments: ** Comment from web user: MartinRobins **

Please find attached a VS2013 project that reproduces the problem. Apologies for the size of the project, it is perhaps a little more complicated that I would have liked but I decided to try and keep it as true to the original as possible.

If you build the project (you will need to download some nuget packages - including v2.4 of the community edition of your own libraries) and then run it you will see a list on screen with a number of your controls. Each of the CheckComboBox controls should have at least one item selected from the available options.

Now drag the bottom of the window up and down quickly a few times so that the items scroll in and out of view. After doing this a few times you will see that some of the CheckComboBox controls start to show no selection. You can also see when this happens by setting a breakpoint on the Surcharges setter on the ListItemViewModel class.

If you repeat the process but first modify the MainWindow XAML adding VirtualizingPanel.IsVirtualizing="False" to the ListView control, you will see that CheckComboBox controls retain their values throughout the scrolling/resizing.

Thanks for looking into this.

Martin.