Getting 7 rows of text is name "App.Model.Folder" when using hub?

I don't have enough to upload a photos.

Here xaml:

<HubSection MinWidth="865" MaxWidth="865" Header="effort english">
                                    <DataTemplate>
                                        <Grid>
                                            <Grid.RowDefinitions>
                                                <RowDefinition Height="auto"></RowDefinition>
                                                <RowDefinition Height="auto"></RowDefinition>
                                                <RowDefinition Height="auto"></RowDefinition>
                                            </Grid.RowDefinitions>
                                            <Grid Grid.Row="0" Height="40">
                                                <Grid>
                                                    <Grid.ColumnDefinitions>
                                                        <ColumnDefinition Width="auto"></ColumnDefinition>
                                                        <ColumnDefinition Width="auto"></ColumnDefinition>
                                                        <ColumnDefinition Width="auto"></ColumnDefinition>
                                                    </Grid.ColumnDefinitions>
                                                    <Grid Grid.Column="0">
                                                        <StackPanel Orientation="Horizontal">
                                                            <TextBlock Text="Filter by unit :" Foreground="Black"></TextBlock>
                                                            <ComboBox x:Name="combunit" SelectionChanged="combunit_SelectionChanged" Loaded="combunit_Loaded" ItemsSource="{Binding Source={StaticResource comboviewunit}}" DisplayMemberPath="{Binding title}">

                                                            </ComboBox>
                                                        </StackPanel>
                                                    </Grid>
                                                </Grid>

Here additional on xaml:

    <Page.Resources>
 </CollectionViewSource>
        <CollectionViewSource x:Name="comboviewunit"></CollectionViewSource>
    </Page.Resources>

Here code in class:

class MainFolder
    {
        List<Folder> folder;
        public object query_unit()
        {
            XDocument xml = XDocument.Load(@"Model/XMLEffort.xml");
            List<Folder> data = (from q in xml.Elements("effort").Elements("English")
                               group q by q.Element("foder").Value into g
                               select new Folder
                               {
                                   title = (string)g.Key,                                 
                               }).ToList();
            return data;
        }

Here folder class

public class Folder
{
    public string title
    {
        get;
        set;
    }

THat result is 17 rows of text is name "App.Model.Folder".(link images:http://ift.tt/1Cn3qfI)