How to intercept programatically close and expand of listgrid group

[Jkike]

Hi,

I hope someone would lead me to the right direction.

I need to handle the event of goup collapsing and group expanding of a listgrid.

I already found that I can intercept the collapse/expande event when is done by clicking on the group row, but I also need to intercept it when it's done programmatically.

I read I can build a custom handler event, but I do not understand how to be notify of the change of the openProperty of the node.

Thank you very much for any help you may give me,
Barbara