ItemsControl Not Creating ContentPresenter - wpf

Question

Why isn't my ItemsControl creating a ContentPresenter for each item? I'm guessing this is what's making my items not show up (they're set to visible and in the right spot when I inspect using the Live Visual Tree). I'm basically reusing code that works up above in a different ItemsControl and I haven't been able to find anything while searching Google/Stackoverflow with this issue. I can include view model code but I don't think it's related because I see the appropriate values in the Live Property Explorer and can see each WellContainer is in it's appropriate grid cell.
XAML:
<ItemsControl
Grid.Row="1"
Grid.Column="1"
ItemsSource="{Binding Wells}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Grid
x:Name="m_WellGrid"
Margin="5"
wpf:GridHelpers.RowCount="{Binding RowCount}"
wpf:GridHelpers.ColumnCount="{Binding ColumnCount}">
</Grid>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style>
<Setter
Property="Grid.Row"
Value="{Binding Path=WellRow}"/>
<Setter
Property="Grid.Column"
Value="{Binding Path=WellCol}"/>
</Style>
</ItemsControl.ItemContainerStyle>
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock
Text="A"
Margin="4"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Live Visual Tree Inspection:

Answer 1

The ItemsControl is designed to wrap the items in a container only when necessary, that is, when the item is not eligible to be its own container. From your comment we find that WellContainer derives from Control, thus is eligible to be its own container1 and is not wrapped in a ContentPresenter. Unfortunately there's no way to control this behavior directly, but you could subclass ItemsControl and override the ItemsControl.IsItemItsOwnContainerOverride method to modify the default behavior.
1 As we can see in the ItemsControl source code it is enough for the item to be of UIElement type to be eligible to be its own container.