Tree size for TreeByNesting UI Element

Hi

I have table and a Tree embedded in it.

I have mapped a value Attribute to the table property for no of rows to visible.

When the User Expands a Tree node I am trying to use onActionLoad Children to find out no of children and try to set the same to the value Attribute.

But there is no event getting generated when user Collapses the tree Node to determine the size of the Table.

please let me know in case we can achive the same by other means.

Thank you

Regards

Krishna Kanth