massupdate : grappelli's autocomplete widget doesn't work

[olivierdalang]

Hi !

When using grappelli's autocomplete feature for foreign keys, the widget doesn't work in massupdate.

It seems the javascript is loaded properly, but the URL to load the values in ajax is wrong :
http://127.0.0.1:8000/grappelli/lookup/autocomplete/?term=blablabla&app_label=false&model_name=false&query_string=false
instead of
http://127.0.0.1:8000/grappelli/lookup/autocomplete/?term=blablabla&app_label=BaseFoncier&model_name=ilot&query_string=_to_field=id
So the ajax query fails (500 error) and the widget is unusable.

It's as if the widget was properly rendered but didn't know about the context.
I tried to look at the source to see if it is an easy fix, but it's a bit over my skills.

Thanks !