By the time being, a custom DataTemplate can be applied only for the EditorTemplate. When the EditMode is Single, a plain TextBlock is used for a readonly PropertyDefinition. With the Default EditMode, if the EditorTemplate is set, it will be displayed, but the user needs to stick to the default behavior provided by the ReadOnlyEditorState property (grayed out and disabled element for its Disabled value, and enabled interaction for the ReadOnly one). Provide an option to directly set a ReadOnlyTemplate for both EditModes.