The DataGrid support is for Composites in a DataGrid at this time.
For a regular DataSet, in contrast, I merely provide basic examples using the free, open-source DataGrid available from the Extended WPF Toolkit™ Community Edition here: http://wpftoolkit.codeplex.com/
In other words, the cells in a DataSet-based DataGrid are NOT considered "composites" but atomic values. The DataGrid itself could be added to a Composite such as it is added to a StackPanel in a TabControl in the Demo App. It is convenient to use
this separate DataGrid for this purpose since it resides in a separate namespace.
Also, in the demo app, AdornerDecorator is leveraged for field validation of TextBoxes, showing an example that dynamically displays a red box around invalid fields. In the DataSet-based DataGrid, I handled things differently--I merely added an extra column
for displaying validation-related error messages. In general, I've avoided leveraging WPF Validation Rules and IDataErrorInfo primarily due to lack of time on my part to consider a "WPF Composite"-esque way to leverage them
Potential future IParent controls that are not currently supported at this time may include ViewBox, StatusBar (this can be achieved with a horizontal stackpanel?), Ribbon, NavigationWindow, ContextMenu, RichTextBox, and FlowDocumentViewer. These controls could
still be used in a WPF Composites app just not as IParents yet.
Ideally, these parents shouldn't just implement IParent, but should also have a thorough set of "convenience" extension methods as well. I could use a lot of help implementing each.
If you would like to "adopt a control" to fully extend and support, please let me know!