How To Auto Expand Tree Table Node

Hi frds,

I have created Tree Table assignment block and there are 3 node of each header entity. My requirement is to auto expand all the node when user open Lazy assignment block. Please suggest how can we achieve this task.

Example: When user open assignment block then all the node of tree table should be defaulty OPEN. so that there is no need to open each node individually.

Thanks

Imran