code: def make_callback_children(self, name, *args, **kwdargs):
          
          if hasattr(self, 'objects'):
              # Invoke callbacks on all our layers that have the UI mixin
              num = len(self.objects) - 1
              while num >= 0:
                  obj = self.objects[num]
                  if isinstance(obj, Callbacks):
                      obj.make_callback(name, *args, **kwdargs)
                  num -= 1
  
          return super(UIMixin, self).make_callback(name, *args, **kwdargs)
docs: Invoke callbacks on all objects (i.e. layers) from the top to
          the bottom, returning when the first one returns True.  If none
          returns True, then make the callback on our 'native' layer.