Major Description
If for a tree update we call AbstractTree.updateTree() method without parameters, the data in tree doesn't update. If we call AbstractTree.updateTree(AjaxRequestTarget target) method - the data updates correctly. The reason is in getting target in AbstractTree.updateTree() method. It's supposed that abstractRequestTarget is getRequestCycle().getActiveRequestHandler(), but actually abstractRequestTarget is getRequestCycle().getRequestHandlerScheduledAfterCurrent().
May be instead of getRequestCycle().getActiveRequestHandler() we must call AbsractRequestTarget.get() in AbstractTree.updateTree() method to get the correct target?
In quickstart project you'll see 3 trees, the first - updates with passed as parameter in onClick() target, the second - updates with target AbsractRequestTarget.get(), the third doesn't updates, because AbstractTree.updateTree() called.