ipython in zope3 zopectl debug

The solution in my earlier post doesn't fly in zope3. To get it to work in zope3 I modified:
~/instances/z3/bin/debugzope

if __name__ == '__main__':    db = startup()
     del startup
     from zope.app.debug import Debugger
     debugger = app = Debugger.fromDatabase(db)
     root = app.root()
     del db
     del Debugger
     import IPython
     IPython.Shell.IPShell(user_ns={'root': root,
                                     'app': app,                         
                                    'top' : app.root() 
                                     }).mainloop(sys_exit=1)

I haven't figured out much about how the debugger differs in Zope3. But it gives me top as app.root().

In [1]: print top.items()
<OOBTreeItems object at 0x355c598>

In [2]: app.root()['foo']
Out[2]: <zope.app.folder.folder.Folder object at 0x36dfef0>

In [3]: top
Out[3]: <zope.app.folder.folder.Folder object at 0x36a27f0>

In [4]: top['foo']
Out[4]: <zope.app.folder.folder.Folder object at 0x36df830>

In [5]: print [x for x in top.items()]
[(u'foo', <zope.app.folder.folder.Folder object at 0x36df830>)]