Does “onRowCreated” event not fire for the top most parent?

Fires well for me.
Please, make sure that you attach the event before the data loading.

If the problem still occurs for you please, provide with a sample of your code or with a complete demo, where the problem can be reproduced.
Here you can find a tutorial about creating a complete demo:
docs.dhtmlx.com/auxiliary_docs__ … pport.html