I posted in MSDN Forum a while ago that I ran into a WPF bug that occurs when you put one template inside another template like <ListBox HorizontalContentAlignment=... VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Background="Honeydew" ItemsSource="{Binding}"> <ListBox.ItemTemplate> <DataTemplate> <ListBox ItemsSource="{Binding}"> <ListBox.ItemTemplate> <DataTemplate> <etc.............. </DataTemplate> </ListBox.ItemTemplate> </ListBox>...