Hi David,
Thank you for your interest in Syncfusion Products.
To display context choice for the custom class instance, we need to trace the objects of the custom class and store it and then need to display the context choice accordingly. I have created a simple sample that traces out the instances of Car class and will display context choice when we press '.' after the Car instance. Please refer to the sample in the following link that illustrates this:
http://websamples.syncfusion.com/samples/Tools.Windows/F78974/Main.htmPlease let me know if any concerns.
Regards,
Fathima