raw_id fields on tree - popup breaks down

What steps will reproduce the problem?
1.Use raw_id_fields on parent (because the list is too long) (with fiencms)
2.click on widget, popup opens 
3.try to expand/collapse a tree

What is the expected output? What do you see instead?
Expected output is expand/collapse.
What happens is select

What version of the product are you using? On what operating system?
Trunk, linux

Please provide any additional information below.

Django, Grappelli, FineCMS (just for tree).

Original issue reported on code.google.com by adikc...@gmail.com on 18 Oct 2010 at 8:59

google-code-export / django-mptt

raw_id fields on tree - popup breaks down #76