are few ways that you can populate the Items of the RadRibbonView hierarchically:
- using ItemContainerStyle, like you did. In this case due to the hierarchical nature of the control you need to set the ItemContainerStyle of your "groupStyleForRad" style to null, in order to stop the template from propagating to its children.
- using implicit styles and directly bind the ItemsSource properties without ItemContainerStyle;
- using HierarchicalDataTemplates, you can find such implementation in our online MVVM ribbon demo;
I hope this information helps. Please let us know if you need further assistance.