You can see from the XAML below that I am binding the ItemSource for the RadPaneGroup to a collection using an extension. The newly greated RadPaneGroup does correctly bind to the collection of panes so I had assumed that the DataTemplate too would be applied.
Thanks
Paul
<Grid>
<TelerikDocking:RadDocking>
<TelerikDocking:RadDocking.DocumentHost>
<TelerikDocking:RadSplitContainer>
<TelerikDocking:RadPaneGroup Extension:PaneGroupExtensions.ItemsSource="{Binding Panes, Source={StaticResource QueueWindowViewModel}}">
<Extension:PaneGroupExtensions.ItemHeaderTemplate>
<DataTemplate>
<Grid>
<Root:EditableContentControl Content="{Binding HeaderText, Mode=TwoWay}"/>
</Grid>
</DataTemplate>
</Extension:PaneGroupExtensions.ItemHeaderTemplate>
</TelerikDocking:RadPaneGroup>
</TelerikDocking:RadSplitContainer>
</TelerikDocking:RadDocking.DocumentHost>
</TelerikDocking:RadDocking>
</Grid>