Cannot delete grabbers

[Deepy]

When trying to delete a grabber I've created I get the following error:

Failure: TypeError: Object <"Instance" of Quotient.Grabber.ScrollingWidget> has no method 'showErrorDialog' caught while calling method "performAction"
Please retry

        Traceback (most recent call last):
          File "/home/alex/divtest/lib/python2.6/site-packages/Nevow-0.10.0-py2.6.egg/nevow/athena.py", line 574, in renderHTTP
            response = self.messageDeliverer.basketCaseReceived(ctx, messageData)
          File "/home/alex/divtest/lib/python2.6/site-packages/Nevow-0.10.0-py2.6.egg/nevow/athena.py", line 869, in basketCaseReceived
            self.livePage.liveTransportMessageReceived(ctx, msg)
          File "/home/alex/divtest/lib/python2.6/site-packages/Nevow-0.10.0-py2.6.egg/nevow/athena.py", line 1452, in liveTransportMessageReceived
            method(ctx, *args)
          File "/home/alex/divtest/lib/python2.6/site-packages/Nevow-0.10.0-py2.6.egg/nevow/athena.py", line 1465, in action_call
            result = defer.maybeDeferred(func, *args, **kwargs)
        --- <exception caught here> ---
          File "/home/alex/divtest/lib/python2.6/site-packages/twisted/internet/defer.py", line 134, in maybeDeferred
            result = f(*args, **kw)
          File "/home/alex/divtest/lib/python2.6/site-packages/xmantissa/scrolltable.py", line 693, in performAction
            return method(item)
          File "/home/alex/divtest/lib/python2.6/site-packages/xquotient/grabber.py", line 849, in action_delete
            grabber.delete()
          File "/home/alex/divtest/lib/python2.6/site-packages/xquotient/grabber.py", line 277, in delete
            self.config.scheduler.unscheduleAll(self)
        exceptions.AttributeError: 'GrabberConfiguration' object has no attribute 'scheduler'