Trouble in Tree element

Dear All:

I've created a tree node.

In a action after I update some values, I reconstructed the tree node.

That means I do context invalidate first and create many elements in it

Now my question is when I reconstructed the node, whichever element on the tree in view,the tree will expand all.

I just want to expand the node which one i click.

Did anyone face the same problem?

Any hint would be help, thanks.

Allen