Hi Christian,
In order to display the proper content in the
RadTabItems Content, you need to apply a
ContentTemplate on the
RadTabControl. The
ContentTemplate defines a
DataTemplate that controls how the business data will be visualized inside the content of each tab.
Also I'm not sure if you need a horizontal or vertical alignment of the content of the tabs, but please have in mind that the
TabOrientation property controls that behavior. When set to vertical, the
RadTabControl will make sure to rotate the tabs to display their content horizontally.
I attached a sample solution demonstrating how to setup your control per your requirements. Please have a look at it and let me know if I can further assist you.
All the best,
Tina Stancheva
the Telerik team