Update [ContentProperty("TabHostContent")] to [ContentProperty("Tabs")]
[ContentProperty("TabHostContent")]
public class TabHostView : Shadows
...
public View TabHostContent
{
set =>
throw new NotSupportedException(
"Starting from version 1.3, you can only add TabItem to the TabHostView through the Tabs property");
}
Update
[ContentProperty("TabHostContent")]
to[ContentProperty("Tabs")]