Django admin sortable won't save -

i have in models.py:

class upload(models.model):     discussion = models.foreignkey(discussion, blank=true, null=true)     upload = thumbnailerfield(upload_to='upload/%s/%s' % (datetime.datetime.now().year, datetime.datetime.now().month ))     mimetype = models.charfield(max_length=50, default="application/octet-stream")     order = models.integerfield(blank=true, null=true, default=0) 

and in admin.py:

class uploadinline(admin.stackedinline):     model = upload     = 0     sortable_field_name = 'order' 

and register uploadinline this:

class discussionadmin(contentadmin):     inlines = [         uploadinline     ] 

it displays okay , can add new uploads, ordering doesn't work. resets press save.

any ideas what's happening here? use similar ordering in other places in app , works normally.

i have figured out problem. functionality in question belongs grapelli. when i've had figured out, simple matter of reading docs.

in order work, had add in upload class:

class meta:     ordering = ['order'] 

and it. works okay.