This issue is a result of changes in the telerik ItemsControl class. We made sure its behavior is almost exactly the same as the ItemsControl in WPF. Before we used to set the ItemTemplate as ContentTemplate of the RadTabItems and it worked differently in WPF.
As a result of making the two ItemsControls work the same, it meant that the ContentTemplate will not be assignable from the TabControl easily. This is why we added the two properties: ContentTemplate
This way you can use the ItemTemplate
property to set how the Headers will look and the ContentTemplate
property to set how the content will look. In your case you can remove the ItemContainerStyle and use the two properties directly.
I will write an article for the changes we have introduced and I will post the link here once it is ready, so that the changes will be more transparent.
the Telerik team