Can you send over a sample project demonstrating your scenario. Specifically what we need to know is:
- how you define your custom shape,
- what is the setup of the RadDiagram,
- where and how you define the RadDiagramContainerShape
- where and how you use the code-behind logic that adds the custom shape in the ContainerShape
If you can elaborate more on your scenario and the points above we will be able to better understand your case and assist you to implement your scenario.
In the meantime you can examine the ContainerShape article in our documentation as it provides a deeper insight into the logic of the control.
the Telerik team