title: WPF Binding on Nested ItemControls with Sub Collection
body: <p>I have the following xaml:</p>
  
  <pre><code>&lt;ItemsControl ItemsSource="{Binding ResearchLanguageViewModel.Filters, Mode=OneWay}"&gt;
      &lt;ItemsControl.ItemTemplate&gt;
          &lt;DataTemplate&gt;
              &lt;StackPanel&gt;
                  &lt;TextBlock Text="{Binding Path=Type}"&gt;&lt;/TextBlock&gt;
                  &lt;TextBox Text="Search...."&gt;&lt;/TextBox&gt;
                  &lt;ItemsControl&gt;
                      &lt;ItemsControl.ItemTemplate&gt;
                          &lt;DataTemplate&gt;
                              &lt;CheckBox Content="{Binding Path=Values}"&gt;&lt;/CheckBox&gt;
                          &lt;/DataTemplate&gt;
                      &lt;/ItemsControl.ItemTemplate&gt;
                  &lt;/ItemsControl&gt;
              &lt;/StackPanel&gt;
          &lt;/DataTemplate&gt;
      &lt;/ItemsControl.ItemTemplate&gt;
  &lt;/ItemsControl&gt;
  </code></pre>
  
  <p>With the following objects/collection(s):</p>
  
  <pre><code>public class FilterViewModel
  {
      public string Type { get; set; }
      public ObservableCollection&lt;string&gt; Values { get; set; }
  }
  
  public class ResearchLanguageViewModel
  {
      public int FirmCount { get; set; }
      public ObservableCollection&lt;FilterViewModel&gt; Filters { get; set; } 
  }
  </code></pre>
  
  <p>I'm trying to bind on the Filters property and the Type property comes out fine.  However, I am having trouble getting the Values collection of strings to show as a group of checkboxes. Not sure what I'm doing wrong here...</p>