Qreator won't run on 13.04 - exception on drag_source_set_target_list()

Trying to run Qreator on 13.04 gives:

$ quickly run
(qreator:6451): Gtk-WARNING **: Can't pass in construct-only parameters to cancel_button

(qreator:6451): Gtk-WARNING **: Can't pass in construct-only parameters to ok_button

(qreator:6451): Gtk-WARNING **: Can't pass in construct-only parameters to help_button
No handlers could be found for logger "qreator_lib"
Traceback (most recent call last):
  File "bin/qreator", line 47, in <module>
    qreator.main()
  File "/tmp/qreator/qreator/__init__.py", line 63, in main
    window = QreatorWindow.QreatorWindow()
  File "/tmp/qreator/qreator_lib/Window.py", line 48, in __new__
    new_object.finish_initializing(builder)
  File "/tmp/qreator/qreator/QreatorWindow.py", line 122, in finish_initializing
    self.ui.qr_drawingarea.drag_source_set_target_list(None)
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 81, in drag_source_set_target_list
    target_list = Gtk.TargetList.new(_construct_target_list(target_list))
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 58, in _construct_target_list
    for entry in targets:
TypeError: 'NoneType' object is not iterable

It seems the problem comes from the drag_source_set_target_list(None) call, but (as usual) I'm having a hard time finding up-to-date (or any at all) pygobject documentation that can pinpoint whether there were any apy changes that might have caused this.