Tree event to capture a click on "+" sign

Hi,

Is there any event to capture if user clicks on the + sign.
i.e. event to capture that the Tree is expanded.

Thanks,
Swapnil

try onTreeSignClicked

Alex,

If I use "onTreeSignClicked" then its treating it as NODE and the tree is not expanding. Also its triggering the onClick even too.
Can u plz let me know the exact event?
I want to use event to capture click on "+" sign as well as "onItemClicked" event separately.
any help is appreciated.

Thanks,
Swapnil.