In my APP. Need to use Lazy Loading, so I have to handler the expand event.
I’m using dijit.Tree on Dojo library. In the document API doesn’t have onCollapse/onExpand event.
I have tried to handler onClick event, The event was fired but not well at all, because on click at collapse symbol, Nothing happens.

Have any idea to handler that event ?
I believe
onOpenevent might be what you are looking for. Check also this thread.