Filtering hierarchial data grid not working on collapsed nodes

Filtering doesn't apply to collapsed nodes. You can try it from the demo
collapse the node => Filter name: contains "rep"
Best regards,

This is expected since data for collapsed rows are not yet loaded.

Ok any hints on how I can implement this functionality?
Seems like a must have feature of a grid.
A working solution is to expand all nodes when applying a filter. Is there an equivalent to onfiltering event?

The whole magic is here:

feel free to submit pull request!