Django admin's filter_horizontal (& filter_vertical) not working

I'm trying to use ModelAdmin.filter_horizontal and ModelAdmin.filter_vertical for ManyToMany field instead of select multiple box but all I get is:

My model:

class Title(models.Model):
    #...
    production_companies = models.ManyToManyField(Company, verbose_name="компании-производители")
    #...

My admin:

class TitleAdmin(admin.ModelAdmin):
    prepopulated_fields = {"slug": ("original_name",)}
    filter_horizontal = ("production_companies",)
    radio_fields = {"state": admin.HORIZONTAL开发者_开发问答}
    #...

The javascripts are loading OK, I really don't get what happens. Django 1.1.1 stable.

I finally got the solution. The problem was with the field's verbose name - it was str instead of unicode. Moving to unicode helped.

Thanks :-)

I was also looking for this kind of answer. I just found out the value of 'filter_horizontal' must be a list or tuple. So this code:

filter_horizontal = ("production_companies",)

should be changed to:

filter_horizontal = ("production_companies", "production_companies")

Another potential cause for filter_horizontal not working is overriding form.media property that includes the necessary JavaScript files for the widget.