reload tree

Hi!
How can I reloading tree grid?

Thanks.

obj.refresh();

Hi, Alex!
Thanks.
I'm using activewidgets-2.0.2-trial.
I'm loading myTree from database, but updating child node I can only reloading myPage.
How can I reloading tree grid without reloading myPage?

obj.clear(); ???
.........
obj.setViewCount(0); ???

getTree();
obj.refresh();

Many thanks for your product.