docs(grid): update info on nested classes

Author: marin-bratanov

knowledge-base/grid-bind-navigation-property-complex-object.md

@@ -16,9 +16,17 @@ Data that you bind to the grid may have complex objects in its model, not only p
 
 How do I use complex objects in my model and show navigation properties information in the grid?
 
+## Notes
+
+Generally, in such a case the grid must be bound to a parent class/interface that exposes all fields that its inheritors will have, so that the grid can show them. The grid cannot know what may be inherited and how its values relate to the base type it is bound to.
+
+Thus, we recommend that you have all necessary fields in the base class and override them in child classes if needed, otherwise, return an empty string in the main class.
+
+This will let the grid perform operations like sorting and filtering, that will otherwise break. You could implement the `ICopmarer` interface to allow sorting, but this can quickly become cumbersome with the more inheritance there is, and it may also couple the separate implementations.
+
 ## Solution
 
-Use [Templates]({%slug components/grid/features/templates%}). For example:
+If simple display is sufficient, you can use [Templates]({%slug components/grid/features/templates%}). For example:
 
 ````CSHTML
 @using Telerik.Blazor