title: Why are ListView and grouped CollectionViewSource not showing any items?
body: <p>Here is code (minified):</p>
  
  <pre><code>&lt;Page
      x:Class="Compote.HubPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:local="using:Compote"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      DataContext="{Binding HubViewModel, Source={StaticResource Locator}}"
      mc:Ignorable="d" Background="{ThemeResource  ApplicationPageBackgroundThemeBrush}"&gt;
  
      &lt;Page.Resources&gt;
          &lt;DataTemplate x:Key="DefaultItemTemplate"&gt;
              &lt;Border Margin="0,0,0,9.5" Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}"&gt;
                  &lt;Grid&gt;
                      &lt;Image Source="{Binding ImagePath}" Stretch="UniformToFill" Height="170"/&gt;
                      &lt;StackPanel Margin="15,12" VerticalAlignment="Bottom"&gt;
                          &lt;Grid&gt;
                              &lt;Grid.ColumnDefinitions&gt;
                                  &lt;ColumnDefinition Width="*" /&gt;
                                  &lt;ColumnDefinition Width="14.5" /&gt;
                                  &lt;ColumnDefinition Width="Auto" /&gt;
                              &lt;/Grid.ColumnDefinitions&gt;
                              &lt;StackPanel Grid.Column="0"&gt;
                                  &lt;TextBlock Text="{Binding Name}" Style="{ThemeResource CustomListViewItemTextBlockStyle}" /&gt;
                              &lt;/StackPanel&gt;
                              &lt;TextBlock Grid.Column="2" Text="{Binding Price, Converter={StaticResource PriceConverter}}" Style="{ThemeResource CustomListViewItemSecondaryTextBlockStyle}"/&gt;
                          &lt;/Grid&gt;
                          &lt;TextBlock Text="{Binding Description}" Style="{ThemeResource ListViewItemContentTextBlockStyle}" TextTrimming="CharacterEllipsis" /&gt;
                          &lt;TextBlock Text="{Binding Weight, Converter={StaticResource WeightConverter}}" Style="{ThemeResource ListViewItemSubheaderTextBlockStyle}" /&gt;
                      &lt;/StackPanel&gt;
                  &lt;/Grid&gt;
              &lt;/Border&gt;
          &lt;/DataTemplate&gt;
  
          &lt;CollectionViewSource x:Key="CollectionViewSourceCategories" Source="{Binding Categories}" IsSourceGrouped="True" ItemsPath="Items" /&gt;        
      &lt;/Page.Resources&gt;
  
  
  &lt;ListView AutomationProperties.AutomationId="ItemListViewSection4"
            AutomationProperties.Name="Items In Group"
            SelectionMode="None"
            IsItemClickEnabled="True"
            ItemsSource="{Binding Source={StaticResource CollectionViewSourceCategories}}"
            ContinuumNavigationTransitionInfo.ExitElementContainer="True"
            ItemTemplate="{StaticResource DefaultItemTemplate}" AllowDrop="True"&gt;
      &lt;ListView.GroupStyle&gt;
          &lt;GroupStyle HidesIfEmpty="True"&gt;
              &lt;GroupStyle.HeaderTemplate&gt;
                  &lt;DataTemplate&gt;
                      &lt;TextBlock Text="{Binding Name}" /&gt;
                  &lt;/DataTemplate&gt;
              &lt;/GroupStyle.HeaderTemplate&gt;
          &lt;/GroupStyle&gt;
      &lt;/ListView.GroupStyle&gt;
      &lt;ListView.ItemContainerStyle&gt;
          &lt;Style TargetType="ListViewItem"&gt;
              &lt;Setter Property="HorizontalContentAlignment" Value="Stretch" /&gt;
          &lt;/Style&gt;
      &lt;/ListView.ItemContainerStyle&gt;
  &lt;/ListView&gt;
  </code></pre>
  
  <p>As you can see, the <code>CollectionViewSource</code> is binded to the <code>ListView</code> and its <code>IsSourceGrouped</code> property is set to <code>True</code>. <code>Categories</code> contains 2 categories with 3 items in each category. But the <code>ListView</code> doesn't show anything, it's totally empty. What's wrong?</p>