I use RadGridView.

RadGridView horizontalScrollBar move GridViewComboBoxColumn displayed on the screen blanks. But verticalScrollBar no change.

What's the problem?

<telerikGridView:GridViewComboBoxColumn 
                                                Header="AccessibleTimeGroup" 
                                                DisplayMemberPath="Name" 
                                                CellStyleSelector="{StaticResource UserCardCellStyleSelector}" 
                                                DataMemberBinding="{Binding Card.AccessableTimeGroup}" ItemsSourceBinding="{Binding AccessibleTimeGroups}" />

Hi,

I am not sure I understand what the exact problem is. Would you please explain it in more details, including a picture of how the issue appears?
Basically, I noticed you have not configured GridViewComboBoxColumn properly and this could be the reason for the behavior you experience. You can check the ComboBox Column documentation as a reference.

Regards,
Didie
Telerik

Thank you for answer.

The initial screen


and scrollbar move


That is GridViewComboBoxColumn.
Sorry i'm not good at english.

<telerikGridView:RadGridView x:Name="radGridView"
                                            Grid.Row="2"
                                            ItemsSource="{Binding UserCards}"
                                            SelectedItem="{Binding SelectedUserCard, Mode=TwoWay}"
                                            Margin="5" 
                                            SelectionMode="Single"
                                            ShowGroupPanel="False"
                                            AutoExpandGroups="True"
                                            AutoGenerateColumns="False"
                                            RowDetailsVisibilityMode="Collapsed"
                                            RowIndicatorVisibility="Collapsed"
                                            CanUserFreezeColumns="True"
                                            FrozenColumnCount="2">
     <telerikGridView:RadGridView.Columns>
          <telerikGridView:GridViewComboBoxColumn 
                                                Header="{Binding ResourceWrapper.StringTable.AccessibleTimeGroup, Source={StaticResource StringTable}}" 
                                                DisplayMemberPath="Name" 
                                                CellStyleSelector="{StaticResource UserCardCellStyleSelector}" 
                                                DataMemberBinding="{Binding Card.AccessableTimeGroup}" ItemsSourceBinding="{Binding AccessibleTimeGroups}" />
     </telerikGridView:RadGridView.Columns>
</telerikGridView:RadGridView>

Attach files

Hello,

Thank you. As seen on the images, it seems the value disappears as you just scroll a little bit and the combo column is still in view mode.
Looking at your code snippet, I notice you have not specified a SelectedValueMemberPath.  Would you please try configuring this setting fine?

You can also check the Empty Cells in Combobox column article on some problematic scenarios.

If this does not help, may I ask you to isolate the issue in a demo project and send it to us in a support ticket? You can take a look at this blog post for a reference on how to isolate an issue. 

Regards,
Didie
Telerik

Thank you for answer. 
However, other problems found. 
Click another GridViewComboBoxColumn change to a blanks. Only AccessibleTimeGroup changed.
SelectedValueMemberPath problem?

Another GridViewComboBoxColumn source.
<telerikGridView:GridViewComboBoxColumn 
                                                Header="CardStatus" 
                                                DisplayMemberPath="Name" SelectedValueMemberPath="Code" 
                                                CellStyleSelector="{StaticResource UserCardCellStyleSelector}" 
                                                DataMemberBinding="{Binding Card.Status}" ItemsSourceBinding="{Binding CardStatus, Source={StaticResource LocalLocator}}" />

Hello,

Is CardStatus collection a property of the bound business object (UserCard)?
If so, why do you additionally set a Source in your definition:

If not and the CardStatus collection is defined in your model, then you should specify ItemsSource instead:

Regards,
Didie
Telerik

Thank you for answer. 
Been resolved in a different way.