In our suite, we are using RadElements
inside the controls and although they are fully functional some properties are not accessible at design time. These elements are lightweight because they do not require a handle. In this case, you will need to set the DataSource in the code behind.
In addition, I want to mention that this is not related to OpenEdge and works the same way in Visual Studio.
I hope this will be useful. Let me know if you have additional questions.